ASTM A36 Mild/ Low Carbon Steel Properties & Chemical Compositions

by AMC

Posted on March 13, 2024 at 01:37 PM

ASTM A36 Steel Material Properties

Introduction to ASTM A36 Mild/Low Carbon Steel

ASTM A36 stands out as the prime choice for mild and hot-rolled steel applications. Renowned for its exceptional welding properties, it proves versatile across various fabrication processes including grinding, punching, tapping, drilling, and machining.

Unlike cold roll C1018, ASTM A36 boasts a yield strength conducive to easier bending, making it a preferred option for numerous structural projects. While larger diameters are uncommon in ASTM A36 due to the prevalence of C1018 hot roll rounds, its availability extends to rectangle bars, square bars, circular rods, and a spectrum of steel shapes encompassing channels, angles, H-beams, and I-beams.

ASTM A36 Steel Chemical Compositions

Element Content
Carbon, C 0.25 - 0.290 %
Copper, Cu 0.20 %
Iron, Fe 98.0 %
Manganese, Mn 1.03 %
Phosphorous, P  0.040 %
Silicon, Si 0.280 %
Sulfur, S  0.050 %

Properties of A36 Carbon Steel

Property Value
Density 2.84 lb/in^3
Yield strength 36,259 psi
Hardness 83 Rockwell
Magnetism Ferrous magnetic

ASTM A36 Steel Physical Properties

Physical Properties Metric Imperial
Density 7.85 g/cm3 0.284 lb/in3

ASTM A36 Steel Mechanical Properties

Mechanical Properties Metric Imperial
Tensile Strength, Ultimate 400 - 550 MPa 58000 - 79800 psi
Tensile Strength, Yield 250 MPa 36300 psi
Elongation at Break (in 200 mm) 20.0 % 20.0 %
Elongation at Break (in 50 mm) 23.0 % 23.0 %
Modulus of Elasticity 200 GPa 29000 ksi
Bulk Modulus (typical for steel) 140 GPa 20300 ksi
Poissons Ratio 0.260 0.260
Shear Modulus 79.3 GPa 11500 ksi

Equivalent Grades of A36 Carbon Steel

Country standard Equivalent grade
European S235JRG2
German St 37-2
Canadian 260W
Japanese SS400
Indian E250
Chinese Q235B
ISO E 235

Machining of ASTM A36

The machinability rate of ASTM A36 is approximately 72%, with an average surface cutting feed of 120 ft/min. It's important to note that machining ASTM A36 steel poses more challenges compared to AISI 1018 steel, requiring careful consideration and precision in the machining process.

Welding and Heat Treatment of ASTM A36 Mild/Low Carbon Steel

Welding: ASTM A36 steel lends itself to easy welding, accommodating various welding methods, and resulting in welds and joints of exceptional quality.

Heat Treatment: Utilizing standard carburizing and hardening methods applicable to AISI 1018 steel is well-suited for ASTM A36. The steel undergoes several crucial processes:

  • Normalizing: In the temperature range of 899°C to 954°C (1650°F-1750°F).
  • Annealing: Carried out at 843°C to 871°C (1550°F-1600°F).
  • Stress Relieving: Performed at 677°C to 927°C (1250°F-1700°F).
  • Carburizing: Applied at 899°C to 927°C (1650°F-1700°F).
  • Hardening: Executed at 788°C to 816°C (1450°F-1500°F).

Common Forms of ASTM A36 Carbon Steel Material

ASTM A36 carbon steel is versatile and exists in various forms to meet diverse applications:

  • Sheet: Ranging from 0.018” to 0.250” in thickness, A36 sheet metal is employed in automotive bodywork, wall construction, and tank fabrication.
  • Bar: A36 steel bars find structural use, notably as reinforcement in concrete due to its high tensile strength complementing concrete's compressive strength.
  • Plate: A36 steel plates, with a thickness equal to or exceeding 0.25”, provide structural integrity. Widely used in buildings, bridges, oil rigs, automotive, and agricultural applications, these plates serve diverse structural roles.
  • Hot Rolled: The most prevalent form, hot-rolled A36 steel, is crafted at temperatures of 1,562–2,192 °F. This process imparts a rougher surface finish, resulting in work hardening and grain elongation. Hot-rolled A36 is cost-effective compared to cold-rolled A36, given the less labor-intensive production.
  • Annealed: A36 steel undergoes annealing at temperatures between 1,550–1,600 °F. This process removes impurities, reduces brittleness, and influences the microstructure through recrystallization. While enhancing machinability, annealing reduces the hardness of the steel.
  • Cold-Drawn: Cold-drawn A36, produced at lower temperatures, is stronger and harder than hot-rolled steel. With an improved finish, it takes shape as bars, tubes, spindles, and wires. Cold-drawn A36 is favored for applications requiring both strength and aesthetic appeal, such as shafts and finely finished products.

Applications of ASTM A36 Mild/Low Carbon Steel

ASTM A36 steel finds diverse applications across various industries:

  1. Construction: Utilized in bolted, riveted, or welded construction for bridges, buildings, and oil rigs.
  2. Fabrication: Employed in the formation of tanks, bins, bearing plates, fixtures, rings, templates, jigs, sprockets, cams, gears, base plates, forgings, ornamental works, stakes, brackets, and various automotive and agricultural equipment.
  3. Structural Components: Used for crafting components such as frames, machinery parts, and diverse structural elements.
  4. Flame Cutting Applications: Applied in parts obtained through flame cutting, contributing to the construction of parking garages, walkways, boat landing ramps, and trenches.

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