Metal
Selection Guide
Every metal comes with its own benefits and weaknesses, and these properties lend each material to different ideal uses. Selecting the optimal metal alloy for a project is a decision that requires in-depth industry knowledge and research. Different types of metal alloys have unique properties that determine the function of a product, material, or the quality of the equipment manufactured.
Alloys are metallic compounds composed of one metal and one or more metal, or non-metal, elements.
Examples of common alloys include: Steel, a combination of iron (metal) and carbon (non metal). Bronze, a combination of copper (metal) and tin (Metal). Brass, A mixture of copper (metal) and zinc
(metal)
Individual pure metals may possess useful properties, such as good electrical conductivity, high strength, and hardness, or heat and corrosion resistance. Commercial metal alloys attempt to combine these beneficial properties in order to create a metal that is more useful for a particular application than any of its component elements.
The development of steel, for example, required finding the right combination of carbon and iron (about 99% iron and 1% carbon, as it turns out) in order to produce a metal that is stronger, lighter and more workable metal than pure iron.
Thousands of alloy compositions are in regular production, while new compositions are developed regularly.
Accepted standard compositions include the purity levels of constituent elements (based on weight content). The makeup, as well as mechanical and physical properties of common alloys, are standardized by international organizations such ISO, SAE International, and ASTM International.
Production
Some metal alloys are naturally occurring and require little processing to be converted into industrial grade materials. Ferro-alloys such as Ferro-chromium and Ferro-silicon, for instance, are produced by smelting mixed ores and are used in the production of various steels.
Commercial and trade alloys, however, generally require greater processing and are most often formed by mixing molten metals in a controlled environment. Yet, one would be mistaken in thinking that alloying metals is a simple process.
Copper
Copper offers some of the best available conductivity (100%), behind only silver and gold in its performance. Copper is also known for its corrosion resistance to industrial atmospheres, water, non-oxidizing acids, alkalis, and neutral saline solutions. While it doesn’t react with water, copper gradually forms a brownish-black oxide when exposed to atmospheric oxygen. Unlike rust, this oxide will actually protect the copper underneath from further corrosion.
Copper is very malleable, ductile, and responsive to precision tooling. For automotive and electrical stamped part applications, it is best used at 0.010” – 0.050” thickness.
Copper alloys commonly used at Keats are: C102, C110, C122, C194 & C197.
Our copper part highlights include reel to reel terminals, loose terminals, conductive lead frames, grids, wire forms, clips, antennas, and prototype and short-run parts. Our custom metal stamping portfolio also includes beryllium copper springs for use in hearing aid applications.
Phosphor Bronze
A specialized alloy of copper, phosphor bronze contains up to 10% tin and up to 1% phosphorous, which provides deoxidizing during melting. While phosphor bronze lacks copper’s extreme conductivity (only 15%), it allows for electrical connections to devices at ultra-low temperatures due to its fair electrical performance combined with very low thermal conduction.
Phosphor Bronze is also insensitive to stress corrosion cracking and offers good corrosion resistance to seawater and industrial atmospheres. Known for its toughness, strength, and low coefficient of friction, phosphor bronze is a popular choice for springs, bolts, and heavy fatigue applications. It is best used at 0.008” – 0.050” thickness for automotive and electrical applications.
Phosphor Bronze alloys commonly used at Keats are: C510, C511, C519 & C521.
Our bronze stamping portfolio includes reel to reel terminals, contacts, loose terminals, conductive lead frames, grids, and prototype and short-run parts.
Brass
Often the most cost-effective choice for electrical applications because of its lower price point than pure copper, brass is known for its malleability, hardness, and resistance to corrosion, not to mention its pleasing appearance. Made by blending copper and zinc, it offers higher malleability than bronze or zinc alone. Nearly 90% of its alloys are, in fact, a result of these materials being recycled!
Brass offers good resistance to fresh water, neutral or alkaline saline solution, organic compounds, and standard atmospheres at sea, on land, and in manufacturing. Adding aluminum to a brass alloy can strengthen its given corrosion resistance while adding lead can enhance its machinability.
With a solid conductivity of 28%, brass is common in automotive and electrical applications at thicknesses up to 0.050”.
Brass alloys commonly used at Keats are: C210, C220, C230, C260, C268 & C272.
Our brass part highlights include reel to reel terminals and contacts, loose terminals, contacts, conductive lead frames, grids, brush guards and holders, and prototype and short-run parts.
Aluminum
An extremely popular material choice, aluminum is likely best known for its exceptional strength-to-weight ratio, making it ideal for strong, lightweight parts, both on its own and in combination with other metals.
Aluminum
Aluminum is also known for its corrosion resistance — it is tolerant to moisture and most chemicals — as well as its low density. The metal offers 61% conductivity and is capable of thermal and electrical superconductivity, as well.
Soft, durable, lightweight, ductile, and malleable, aluminum is popular for automotive and mechanical components at thicknesses ranging from 0.012” to 0.120”.
Aluminum alloys commonly used at Keats are: 3003, 1100, 5056, 5052 & 5154.
Our aluminum part highlights include clips, clamps and flat springs, brackets, latches, covers, wire forms, antennas, and prototype and short-run parts.
Steel
Annealed, cold-rolled, stainless — there are countless steel alloys designed to suit any industry. A classic combination of iron with carbon and any number of other elements, steel is created by reducing the carbon in iron ore and replacing it with materials to alter traits such as strength, conductivity, and corrosion resistance. In addition, heat treating processes such as annealing, quenching, and tempering can alter the material and its end performance.
Steel is typically resistant to corrosion with a wide conductivity range (up to 15%) and great formability and durability. A low-cost option, it presents good baseline tensile and yield strength. However, all of these properties can vary greatly, offering a wide array of choices to create the perfect fit for a particular project. Annealed steel, for example, is far more ductile and fracture-resistant than its counterpart prior to heat treatment, and G1050 is an alloy specifically created for versatility and machinability in engineering applications.
CARBON STEEL
Carbon steel is commonly used across many industries. It is affordable while still providing excellent mechanical properties. Carbon steel is typically composed of 0.05% to about 2.0% carbon measured by weight, along with iron and trace amounts of other elements. Since it is a very common selection for a variety of purposes, it is important to know how to choose the right carbon steel grade for your project. Below are some 7 things to consider when choosing a carbon steel grade.
Does the carbon steel need to be machined?
There are many types of carbon steel that can be easily machined, but there are also many that may prove to be difficult. Grades of lower carbon steel such as C1010 and C1018 have good machinability. Alternatively, carbon steel with higher amounts of carbon such as C1141 and C1144 can also be machined without difficulty due to the sulfur that is added to their chemical composition. C1045 has a higher carbon content but no additional elements to aid in machining, making it a poor choice if machining is required.
Does the carbon steel need to be welded?
Certain types of carbon steel have very good weldability, however, there are several considerations to take into account when selecting a carbon steel to be welded. First, grades such as C1141 and C1144 that are great for machining are typically not weldable. The sulfur found in these grades can cause weld solidification cracking to occur. Grades with low carbon such C1018 and A36 (or 44W in Canada) would be a better choice as they are readily welded. Higher carbon grades such as C1045 can also work, but may require preheat or post weld heat treatment.
What are the strength requirements of the carbon steel?
Low carbon steels tend to be lacking in terms of tensile strengths, comparative to other carbon steels. These should be avoided if high strengths are required. Choosing a carbon steel grade with a higher carbon content such as C1045 can provide more strength and hardness than a low carbon grade like C1008. However, a low carbon alternative is high-strength low-alloy steel (HSLA) which is a low carbon based steel specifically designed to possess higher strengths, while retaining formability.
Does the carbon steel require good formability?
Since carbon steel is such a broad category, many different combinations of mechanical properties can be achieved. If ductility is desired, lower carbon grades such as C1008 and C1010 should be considered. If you require sheet, consider using a DQ or DQAK grade. As a rule of thumb, lower carbon steels are much easier to form than higher carbon steels.
Does the carbon steel need to be heat-treatable?
Carbon steels with amounts of carbon greater than 0.30% by weight, such as C1045 and C1141 can be heat-treated with ease. Another option could be steels that have a carbon content that is just over 0.20% by weight. These carbon steels, such as A36, may have trace amounts of other elements added to them to increase their hardenability. Low carbon steels, those having carbon contents under 0.20%, are not capable of being easily heat treated. The lack of carbon does not allow the steel crystalline structure martensite to form, which gives carbon steel higher hardness and strength.
Does the carbon steel need to have good corrosion resistance?
It is not common for carbon steels to be chosen for their ability to resist corrosion. They are mostly composed of iron which can oxidize, forming rust. Without enough corrosion resistant elements added to their chemical composition, such as chromium, nothing prevents the iron from oxidizing. Choosing a galvanized or plated carbon steel is a viable option to prevent corrosion. Alternatively, adding oil or paint to the surface of a carbon steel is a good way to help prevent iron oxidation from occurring.
Applications
Knowing common applications of different grades of carbon steel can help you choose the right grade for your project. Here are some typical uses:
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Grade A36 / 44W: automotive components, cams, fixtures, tanks, forgings and structural applications such as buildings or bridges.
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Grades C1008, C1010, and C1018: machinery parts, tie rods, relatively low strength structural applications, mounting plates and brackets.
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Grade C1045: bolts, gears, crank shafts, cylinder shafts, die forges, and applications where more strength or higher hardness is required than that of C1008 or C1010.
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Grades C1141 and C1144: Pins, studs, bolts, shafts, tie rods and applications similar to those of C1045 when machinability is very important.
CARBON STEEL 1010
Topics Covered
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Introduction
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Chemical Composition
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Physical Properties
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Mechanical Properties
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Thermal Properties
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Other Designations
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Machinability
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Forming
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Welding
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Heat treatment
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Forging
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Hot Working
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Cold Working
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Annealing
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Tempering
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Hardening
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Applications
Introduction
AISI 1010 carbon steel is a plain carbon steel with 0.10% carbon content. This steel has relatively low strength but it can be quenched and tempered to increase strength.
The following datasheet provides more details about AISI 1010 carbon steel.
Chemical Composition
The following table shows the chemical composition of the AISI 1010 carbon steel.
ElementContent (%)
Iron, Fe99.18-9.62 %
Manganese, Mn0.30-0.60 %
Sulfur, S≤0.050 %
Phosphorous, P≤0.040 %
Carbon, C0.080-0.13 %
Physical Properties
The physical properties ofAISI 1010 carbon steel are outlined in the following table.
PropertiesMetricImperial
Density7.87 g/cm30.284 lb/in³
Mechanical Properties
The mechanical properties of AISI 1010 cold drawn carbon steel are tabulated below.
PropertiesMetricImperial
Tensile strength365 MPa52900 psi
Yield strength (depending on temper)305 MPa44200 psi
Elastic modulus190-210 Gpa27557-30458 ksi
Bulk modulus (typical for steel)140 GPa20300 ksi
Shear modulus (typical for steel)80.0 GPa11600 ksi
Poisson’s ratio0.27-0.300.27-0.30
Elongation at break (in 50 mm)20%20%
Reduction of area40%40%
Hardness, Brinell105105
Hardness, Knoop (converted from Brinell hardness)123123
Hardness, Rockwell B (converted from Brinell hardness)6060
Hardness, Vickers (converted from Brinell hardness)108108
Machinability (based on AISI 1212 steel as 100 machinability. The machinability of group I bar, rod, and wire products can be improved by cold drawing)5555
Thermal Properties
The thermal properties of AISI 1010 carbon steel are tabulated below.
Properties Metric Imperial
Thermal expansion co-efficient (@0.000-100°C/32-212°F)12.2 µm/m°C6.78 µin/in°F
Thermal conductivity (typical for steel)49.8 W/mK346 BTU in/hr.ft².°F
Other Designations
Equivalent materials to AISI 1010 carbon steel are as follows.
AMS 5050AMS 5055AMS 7225DIN 1.1121AMS 5040AMS 5042
ASTM A512 (1010, MT 1010)ASTM A513 (1010, MT 1010)ASTM A519 (1010, MT 1010)ASTM A787 (MT 1010)MIL S-11310 (CS 1010)ASTM A513 Type 2
JIS S12CJIS S1OCJIS S9CKAFNOR XC 10ASTM A513 Type 3SAE J414
ASTM A635ASTM A830AMS 5044AMS 5047AMS 5053ASTM A108
SAE J1397ASTM A29ASTM A510ASTM A519ASTM A545ASTM A549
ASTM A575ASTM A576SAE J403SAE J412
Machinability
The machinability of AISI 1010 carbon steel, especially in the cold drawn or cold worked state, is considered as fairly good.
Forming
AISI 1010 carbon steel has good formability and ductility, and can be easily formed using conventional methods.
Welding
AISI 1010 carbon steel can be welded using all the conventional welding techniques.
Heat treatment
AISI 1010 carbon steel is mostly used in the annealed or case hardened condition. However, it can also be heat treated, quenched and tempered but the cost for performing these processes are very high.
Forging
Forging can be performed on AISI 1010 carbon steel between 1260 and 982°C (2300 and 1800°F).
Hot Working
The hot working capacity of AISI 1010 carbon steel is between the ranges of 482 to 93°C (900 to 200°F).
Cold Working
The cold working capacity of AISI 1010 carbon steel is good. In cases where severe cold working is performed stress relief or full anneal has to be performed.
Annealing
A full anneal process can be performed for AISI 1010 carbon steel at 871 to 982°C (1600 to 1800°F), which is followed by slow cooling process in the furnace. A stress relief anneal process can also be done at 538°C (1000°F) and then gradually cooled. AISI 1010 carbon steel in the full annealed condition has a tensile strength of about 45 ksi.
Tempering
Tempering can be performed on AISI 1010 carbon steel, after hardening process is completed, at 316 to 593°C (600 to 1100°F). This depends upon the strength level that is required. When tempering is performed at 538°C (1000 F), the tensile strength will be about 75 ksi.
Hardening
20
Applications
AISI 1010 carbon steel is primarily used for applications such as cold headed fasteners and bolts.
1018 CARBON STEEL
Topics Covered
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Introduction
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Chemical Composition
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Physical Properties
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Mechanical Properties
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Electrical Properties
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Machining
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Weldability
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Heat Treatment
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Normalizing
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Forging
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Tempering
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Annealing
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Stress Relieving
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Case Hardening
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Core Refining
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Carburizing
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Applications of AISI 1018 Mild / Low Carbon Steel
Introduction
AISI 1018 mild/low carbon steel has excellent weldability and produces a uniform and harder case and it is considered as the best steel for carburized parts. AISI 1018 mild/low carbon steel offers a good balance of toughness, strength and ductility. Provided with higher mechanical properties, AISI 1018 hot rolled steel also includes improved machining characteristics and Brinell hardness.
Specific manufacturing controls are used for surface preparation, chemical composition, rolling and heating processes. All these processes develop a supreme quality product that are suited to fabrication processes such as welding, forging, drilling, machining, cold drawing and heat treating.
Chemical Composition
ElementContent
Carbon, C0.14 - 0.20 %
Iron, Fe98.81 - 99.26 % (as remainder)
Manganese, Mn0.60 - 0.90 %
Phosphorous, P≤ 0.040 %
Sulfur, S≤ 0.050 %
Physical Properties
Physical PropertiesMetricImperial
Density7.87 g/cc0.284 lb/in3
Mechanical Properties
Mechanical PropertiesMetricImperial
Hardness, Brinell126126
Hardness, Knoop (Converted from Brinell hardness)145145
Hardness, Rockwell B (Converted from Brinell hardness)7171
Hardness, Vickers (Converted from Brinell hardness)131131
Tensile Strength, Ultimate440 MPa63800 psi
Tensile Strength, Yield370 MPa53700 psi
Elongation at Break (In 50 mm)15.0 %15.0 %
Reduction of Area40.0 %40.0 %
Modulus of Elasticity (Typical for steel)205 GPa29700 ksi
Bulk Modulus (Typical for steel)140 GPa20300 ksi
Poissons Ratio (Typical For Steel)0.2900.290
Machinability (Based on AISI 1212 steel. as 100% machinability)70 %70 %
Shear Modulus (Typical for steel)80.0 GPa11600 ksi
Electrical Properties
Electrical resistivity @0°C (32°F)0.0000159 Ω-cm0.0000159 Ω-cmannealed condition
@100 °C/ 212 °F0.0000219 Ω-cm0.0000219 Ω-cmannealed condition
@ 200 °C/392 °F0.0000293 Ω-cm0.0000293 Ω-cmannealed condition
Machining
The machinability of AISI 1018 mild/low carbon steel is graded at 78% of B1112.
Weldability
AISI 1018 mild/low carbon steel can be instantly welded by all the conventional welding processes. Welding is not recommended for AISI 1018 mild/low carbon steel when it is carbonitrided and carburized.
Low carbon welding electrodes are to be used in the welding procedure, and post-heating and pre-heating are not necessary. Pre-heating can be performed for sections over 50 mm. Post-weld stress relieving also has its own beneficial aspects like the pre-heating process.
Heat Treatment
The heat treatment for AISI 1018 mild/low carbon steel consists of the following processes:
Normalizing
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AISI 1018 mild/low carbon steel should be heated at 890°C – 940°C and then cooled in still air.
Forging
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This process requires heating between 1150°C – 1280°C and AISI 1018 mild/low carbon steel is held until the temperature becomes constant.
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900°C is the minimum temperature required for the forging process.
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The steel is then cooled in air after this process.
Tempering
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AISI 1018 mild/low carbon steel is tempered at between 150°C – 200°C for improvement of case toughness. This process has little or no effect on hardness.
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The occurrence of grinding cracks is reduced when AISI 1018 mild/low carbon steel is tempered at the above mentioned temperature.
Annealing
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The AISI 1018 mild/low carbon steel is heated at 870°C – 910°C and allowed to cool in a furnace
Stress Relieving
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500°C – 700°C is required to relieve stress in AISI 1018 mild/low carbon steel that is later cooled down in still air.
Case Hardening
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This process requires heating to be carried out between 780°C – 820°C. AISI 1018 mild/low carbon steel is then quenched in water.
Core Refining
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This is an optional process that requires heating at 880°C – 920°C.
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AISI 1018 mild/low carbon steel after being heated is moistened in oil or water.
Carburizing
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Carburizing takes place at 880°C – 920°C.
Applications of AISI 1018 Mild / Low Carbon Steel
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It is used in bending, crimping and swaging processes.
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Carburized parts that include worms, gears, pins, dowels, non-critical components of tool and die sets, tool holders, pinions, machine parts, ratchets, dowels and chain pins use AISI 1018 mild/low carbon steel.
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It is widely used for fixtures, mounting plates and spacers.
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It is suitably used in applications that do not need high strength of alloy steels and high carbon.
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It provides high surface hardness and a soft core to parts that include worms, dogs, pins, liners, machinery parts, special bolts, ratchets, chain pins, oil tool slips, tie rods, anchor pins, studs etc.
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It is used to improve drilling, machining, threading and punching processes.
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It is used to prevent cracking in severe bends.
1045 CARBON STEEL
Topics Covered
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Introduction
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Chemical Composition
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Physical Properties
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Mechanical Properties
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Machining
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Welding
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Heat Treatment
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Forging
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Annealing
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Normalizing
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Stress Relieving
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Hardening
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Tempering
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Applications
Introduction
AISI 1045 steel is a medium tensile steel supplied in the black hot rolled or normalized condition. It has a tensile strength of 570 - 700 MPa and Brinell hardness ranging between 170 and 210.
AISI 1045 steel is characterized by good weldability, good machinability, and high strength and impact properties in either the normalized or hot rolled condition.
AISI 1045 steel has a low through-hardening capability with only sections of size around 60 mm being recommended as suitable for tempering and through-hardening. However, it can be efficiently flame or induction hardened in the normalized or hot rolled condition to obtain surface hardnesses in the range of Rc 54 - Rc 60 based on factors such as section size, type of set up, quenching medium used etc.
AISI 1045 steel lacks suitable alloying elements and hence does not respond to the nitriding process.
Chemical Composition
ElementContent
Carbon, C0.420 - 0.50 %
Iron, Fe98.51 - 98.98 %
Manganese, Mn0.60 - 0.90 %
Phosphorous, P≤ 0.040 %
Sulfur, S≤ 0.050 %
Physical Properties
Physical PropertiesMetricImperial
Density7.87 g/cc0.284 lb/in3
Mechanical Properties
Mechanical PropertiesMetricImperial
Hardness, Brinell163163
Hardness, Knoop (Converted from Brinell hardness)184184
Hardness, Rockwell B (Converted from Brinell hardness)8484
Hardness, Vickers (Converted from Brinell hardness)170170
Tensile Strength, Ultimate565 MPa81900 psi
Tensile Strength, Yield310 MPa45000 psi
Elongation at Break (in 50 mm)16.0 %16.0 %
Reduction of Area40.0 %40.0 %
Modulus of Elasticity (Typical for steel)200 GPa29000 ksi
Bulk Modulus (Typical for steel)140 GPa20300 ksi
Poissons Ratio (Typical For Steel)0.2900.290
Shear Modulus (Typical for steel)80 GPa11600 ksi
Machining
AISI 1045 steel has good machinability in normalized as well as the hot rolled condition. Based on the recommendations given by the machine manufacturers, operations like tapping, milling, broaching, drilling, turning and sawing etc. can be carried out on AISI 1045 steel using suitable feeds, tool type and speeds.
Welding
Certain facts about welding of AISI 1045 steel are:
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AISI 1045 steel is readily welded when correct procedure is followed.
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Welding AISI 1045 steel in through-hardened, tempered and flame or induction hardened condition is not recommended.
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Low hydrogen electrodes are preferred for welding AISI 1045 steel.
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The workpiece is
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Pre-heated at 200°C–300°C (392°F - 572°F)
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Maintained at the same temperature during welding
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Cooled slowly using sand, ashes etc and
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Stress relieved at 550°C - 660°C (1022°F - 1220°F).
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Heat Treatment
AISI 1045 is subjected to the following processes:
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Forging
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Annealing
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Normalizing
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Stress relieving
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Hardening
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Tempering
Forging
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Heat to 850°C - 1250°C (1562°F - 2282°F)
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Hold until the temperature is uniform
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Cool in furnace
Annealing
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Heat to 800°C - 850°C (1472°F - 1562°F)
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Hold until the temperature is uniform
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Cool in furnace.
Normalizing
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Heat to 870°C - 920°C (1598°F-1688°F)
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Hold until the temperature is uniform
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Soak for 10 - 15 minutes
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Cool in still air
Stress Relieving
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Heat to 550°C - 660°C (1022°F - 1220°F)
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Hold until the temperature is uniform
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Soak for 1 hour per 25mm of section
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Cool in still air
Hardening
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Heat to 820°C - 850°C (1508°F - 1562°F)
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Hold until the temperature is uniform
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Soak for 10 - 15 minutes per 25mm of section
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Quench in water or brine
Tempering
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Re-heat to 400°C - 650°C (752°F - 1202°F ) as required
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Hold until the temperature is uniform
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Soak for 1 hour per 25mm of section
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Cool in still air
Applications
AISI 1045 is widely used for all industrial applications requiring more wear resistance and strength. Typical applications of AISI 1045 are as follows:
GearsPinsRams
ShaftsRollsSockets
AxlesSpindlesWorms
BoltsRatchetsLight gears
StudsCrankshaftsGuide rods
Connecting rodsTorsion barsHydraulic clamps
TOOL STEEL
Tool steels feature increased amount of carbon and other alloying elements which give them enhanced physical properties, making them the ideal choice for a variety of applications. Cutting tools, cams, dies, chuck jaws, blocks, gauges, and drill bits are just some examples of the many different tool steel applications. Along with many different applications, there are also many different tool steel grades available, including cold-working tool steels that encompass water-hardening tool steels, oil-hardening tool steels, and air-hardening tool steels. There are high-speed tool steels, hot-working tool steels, and shock-resisting tool steels as well. With so many different choices, it is necessary to be able to identify the correct tool steel for the job. Listed in this article are seven things to consider when selecting a tool steel grade.
Will the tool steel be subjected to large impacts?
Tool steels are generally hard and brittle. When impacts occur on materials like this, it can cause fractures. Shock-resisting tool steels are a group made to better withstand impact as they have a higher degree of toughness than other tool steels. However, this increased toughness does come with a reduction in hardness and wear resistance compared to other types of tool steels. Therefore, shock-resisting tool steels should only be used in applications that require the steel to undergo large, sudden impacts. Examples of shock-resisting tool steels are S1, S2, and S5. Shock-resisting tool steels are frequently used in chisels, shears, and hammers.
Will the tool steel be doing work at high temperatures?
High temperatures can affect the mechanical properties of steel. This is especially true of tool steels, because many of them have been heat-treated, and reheating them may render that heat-treatment useless. Hot-work tool steels are a popular option when dealing with high temperature applications because they are less likely to lose their hardness and wear resistance at elevated temperatures. This is because of their relatively high amounts of tungsten and molybdenum. Grades of hot-work tool steels include H12, H13, and H19. They are commonly used for casting dies, extrusion dies, and hot shear knives.
Will the tool steel be used at high speeds?
Some tools are moved so fast that the energy generated can result in elevated temperatures which can impact the tool steel in two ways. The first concern is that the high temperature will reduce the hardness and wear resistance of the tool. The second concern is that since there are many cycles being run on the tool in such a short time, tool wear can occur very quickly. For operations such as these, high-speed tool steels should be used. They are made to not only have mechanical properties that withstand elevated temperatures, but also have high wear resistance to prevent tool degradation when exposed to many cycles in a short time frame. Examples of high-speed tool steels include T1, M7, and M42. They are used in drill bits, cutting blades, and pump components.
Is cost a concern?
For low-budget manufacturing, tool steels with many different expensive alloying elements may not be justifiable. Water-hardening tool steels offer a good compromise of cost and mechanical properties. These grades get most of their enhanced mechanical properties from high amounts of carbon and not from other alloying elements. They are rapidly water quenched to form hard, brittle microstructures that can withstand wear. Examples of water-hardening tool steels are W1, W2, and W3. They are frequently used for low-budget operations that require high wear resistance.
Will the tool steel be performing work at low temperatures?
Cold-work tool steels are ideal for low temperature applications. They consist of air-hardening and oil-hardening tool steels. They do not require as rapid a quench as water-hardening tool steels because of the increased amounts of alloying elements such as chromium, manganese, and molybdenum. This generally makes them more costly than water-hardening tool steels, but with the benefit of enhanced mechanical properties. Examples of these tool steels are D2, O2, and A7. They are used for punches, dies, gages, and many more cold-working applications.
Will it be used for plastic molding?
Plastic molding usually requires the use of a special type of tool steel. This tool steel falls under the Type P family of tool steels. They are generally not used for any other type of tooling applications aside from the manufacture of plastic molds or molds for metals with low melting temperatures. Examples include P2, P3, and P5.
ALLOY STEEL
Alloy steel can be used in a wide variety of applications because there are so many different combinations of alloying elements that achieve different properties. With such a wide variety of alloying elements and combinations, choosing an alloy steel grade can be difficult. This article will explain some considerations when choosing an alloy steel for your next project
Does the alloy steel need to have good formability?
Some elements, such as chromium and boron, increase the steel’s hardenability. Since most alloy steels are able to be hardened, forming is typically done in the annealed state of the material. Alloy steels that are annealed and have lower amounts of alloys and carbon are typically more formable than those with higher amounts of carbon and other alloying elements. AISI 4130 is a good example of an alloy steel that when annealed has relatively good formability when compared with other alloy steels.
Does the alloy steel need to be welded?
Similar to formability, some of the elements added to alloy steels can be detrimental to welding. Be wary of additions of sulfur and boron if you require an alloy steel to be welded as both can induce cracking. Also, if the carbon content in the alloy steel is high, care must be taken to slow the rate of cooling to avoid cracking. The welding of most alloy steels should be performed in the annealed state. AISI 4130 is an example of a very weldable alloy steel. AISI 6150 on the other hand, while weldable, must follow strict preheat and post heat procedures to avoid weld cracking.
Does the alloy steel need to be machined?
The addition of sulfur and phosphorous can help increase the machinability of an alloy steel, while the addition of boron and chromium can decrease machinability. Machining of alloy steels is typically performed in the annealed state because the reduced hardness helps the machining process, but it can also be done after heat treatment. In the annealed condition, AISI 4130 and AISI 8620 are examples of alloy steels that can be machined readily. AISI 4340 is more difficult to machine than AISI 4130 and AISI 8620, even in the annealed state.
Does the alloy steel need to have corrosion resistance?
If corrosion needs to be inhibited (and coating is not an option) then it is important to find an alloy steel grade that has increased corrosion resistance. Alloy steel grades with a higher amount of elements such as chromium, copper, nickel, and molybdenum will generally have a greater resistance to corrosion.
Does the alloy steel need to be heat treated?
One of the main benefits of alloy steel is that it can be easily heat treated. Heating and quenching alloy steels such as AISI 4340 and AISI 6150 can result in very high tensile strengths and hardnesses throughout the thickness of the material when compared with low carbon steel. AISI 8620 is a steel that is commonly carburized which is a form of case hardening. Once carburized, it is very hard and abrasion resistant on the outside layer of the material, but inside the outer “case” it is still ductile and tough.
What strengths are required of the alloy steel?
Depending on the alloying elements used, very high tensile strengths can be achieved. The strength achieved with alloy steel depends on what elements the steel is made up of as well as the heat treated state the alloy steel is in. Alloy steels that are annealed or normalized will have lower strengths than the same ones that are heated and rapidly quenched. It is best to look at a material data sheet to determine what strengths a particular alloy steel can achieve.
Typical applications
Here are some common types of alloy steels and how they are used:
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AISI 4130: Aircraft parts, machine tools, hydraulic tools, ball bearings
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AISI 4140: Shafts, gears, machine tools, hydraulic tools, spindles, sprockets
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AISI 4340: Landing gear, axles, oil and gas extraction, gears, sprockets, spindles
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AISI 6150: Gears, shafts, spindles, tools
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AISI 8620: Fasteners, axles, gears, pins, shafts, springs