1020 Carbon Steel: Uses, Composition, Properties
1020 carbon steel is a low-carbon or “mild” steel which means it has a carbon content below 0.3%. In addition to carbon, 1020 steel contains manganese, sulfur, and phosphorus. The low-carbon content of 1020 steel makes it very well suited to machining, welding, and forming. However, that same chemical property prevents 1020 steel from responding well to heat treatment. Material characteristics result in 1020 steel being used in numerous applications, such as: axles, cold-headed bolts, and machine components.
1020 steel is a low carbon steel material that is mostly produced in the turned and polished or cold-drawn form. 1020 steel is a magnetic iron alloy that conducts electromagnetic waves well.
1020 steel is popular in many forms, such as: angle iron, channel iron, I-beams, H-beams, and various thicknesses of steel plate. The grade is widely used across many heavy industries due to its high weldability and machinability. Furthermore, 1020 steel has good flexibility which makes it useful in applications with shock loading. It is also used to manufacture machinery parts, shafts and camshafts, axles, gudgeon pins, and ratchets.
1020 carbon steel is made by mixing the molten metals and then hot rolling them. This process is similar to most carbon steels, and the only real difference is the chemical composition.
To produce 1020 carbon steel, iron is smelted in a furnace, and coke is added. The impurities are then burnt off. A secondary refining process then takes place in which the steel is added to an LF or RF furnace to carry out further decarburization, desulfurization, and deoxidation until the right chemical composition is achieved. The steel can then be poured into a variety of shapes, in a range of dimensions. The steel can then be either hot-rolled, hot-forged, cold-rolled, or annealed.
1020 steel, as with any other steel, is mostly formed of iron. Iron makes up 99–99.53% of the 1020 steel composition. 1020 also contains 0.3–0.6% manganese and 0.17–0.23% carbon. Any steel with a carbon content lower than 0.3% is classified as low-carbon steel. Table 1 below shows the other elements that are added to make 1020 carbon steel by weight:
The carbon content of 1020 steel is low at 0.17%–0.23% carbon. Steels less than 0.3% carbon are considered low-carbon steels. Low-carbon steels are renowned for their ductility, malleability, and weldability. However, they have a lower strength-to-weight ratio and less corrosion resistance than high-carbon steels.
Table 2 lists some of the properties of 1020 steel:
1020 steel has a machinability rating of 65% when using 1112 carbon steel as a baseline. The recommended cutting rate using a milling machine is 610–820 SFM and using a turning machine 980–1,330 SFM is recommended. For milling, a semi-hard substrate with a PVD coating should be used and for turning a hard substrate with a CVD coating should be used.
1020 carbon steel has a melting point of 2,760 °F. 1020 steel also has a thermal conductivity of 360 BTU-in/(hr-ft2-F), a thermal expansion rate of 6.61*10-6 in/(in*°F) and a specific heat capacity of 0.116 BTU/(lb*F).
Listed below are some common forms of 1020 carbon steel:
1020 steel can be bought in sheet form of thicknesses between 0.018–0.250”. 1020 steel in sheet form is generally used for bodywork panels or to create walls/bulkheads or tanks.
1020 steel is produced in bar form which is often used to make axles, camshafts, gears, gudgeon pins, spindles, and other rotating parts.
Plate form 1020 steel has a thickness greater than 0.250”. 1020 steel plates can be used to produce gusset plates, shim plates, bridge plates, bearing plates, and column bases.
1020 steel is hot-rolled between 900–1,200 °F. By hot rolling 1020 steel, strain is placed on the steel which creates dislocations within the steel's microstructure. The increase in dislocation density results in strain hardening. The hot-rolled form of 1020 steel is cheaper than the cold-drawn form as the hot-rolled process is less labor intensive.
Annealing is carried out at temperatures between 1,600–1,800 °F and then cooled slowly in a furnace which will give a strength of 65 ksi. The process of annealing increases the steel's strength using recrystallization. To recrystallize the steel, it is heated to just below its melting temperature which is the point at which crystals start to form. The steel is then cooled slowly at a specific rate which allows the crystals to grow effectively. This reduces the internal stresses of the steel and removes impurities. The process of annealing also reduces the brittleness and hardness of the steel.
1020 carbon steel can be achieved using conventional methods. The cold-drawn form of 1020 steel will be much stronger, harder, and dimensionally accurate than the hot-rolled form. Cold-drawn steel produces tubes, bars, spindles, and wires. If the 1020 steel experiences an extended period of cold working then the use of stress relief annealing is recommended.
Table 3 below lists the 1020 equivalent standard of steel for other countries. It should be noted that not all standards will be exactly equal and will likely differ slightly in chemical composition and therefore properties:
The main advantage of 1020 steel is that it can be cut and formed without losing toughness in the process. Other advantages of using 1020 steel include:
- High machinability
- Good weldability
- High ductility
The disadvantages of using 1020 when compared to other steels are as follows:
- Less strong
- Less durable
- Less heat resistant
The difference between 1020 steel and A514 steel is that A514 is stronger, harder, and has a higher fatigue strength. Both 1020 and A514 are low-carbon steels with high iron content and a small content of manganese. However, 1020 contains small amounts of phosphorus and sulfur, whereas A514 has chromium, silicon, molybdenum, titanium, vanadium, and boron instead.
This article presented 1020 carbon steel, explained it, and discussed its various applications and properties. To learn more about 1020 steel, contact a Xometry representative.
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