ASTM A36 / A36M standard specification covers carbon structural steel shapes, plates, and bars of structural quality for use in riveted, bolted, or welded construction of bridges and buildings, and for general structural purposes. ASTM A36 / A36M Standard main steel grade:A36 carton steel.
ASTM A36/A36M description
This is a type of weldable carbon engineering structural steel. Its carbon content is usually less than 0.25%, higher than ordinary carbon structural steel
yield point σs or yield strength σ0.2 (30 ~ 80kgf/mm2) and yield ratio σs/σb (0.65 ~ 0.95), it’s better in the hot and cold machinability, good weldability, low cold and brittle tendency, notch and aging sensitivity, as well as better resistance to atmospheric, seawater and other corrosion. Its low content of alloying elements, generally below 2.5%, is used after hot rolling or after simple heat treatment (non-tempered state); ASTM A36 carbon steel is widely used in bridges, rivets, bolt structures, and other structural elements including drilling rigs, electric shovels, electric drive wheels, anti-landmine vehicles, mining vehicles, excavators, loaders.
Related role of ASTM A36/A36M
At present, the new low alloy high strength steels
are characterized by low carbon (≤0.1%) and low sulfur (≤0.015%). The commonly used alloying elements can be classified according to their role in the strengthening mechanism of the steel: solid solution strengthening elements (Mn, Si, Al, Cr, Ni, Mo, Cu, etc.); refinement of grain elements (Al, Nb, V) , Ti, N, etc.); precipitation hardening elements (Nb, V, Ti, etc.) and transformation hardening elements (Mn, Si, Mo, etc.) (see strengthening of metals).
C; The formation of pearlite in the steel or dispersed alloy carbide precipitation, so that the steel is strengthened, can greatly improve the steel's toughness and welding performance.
Mn; High Mn/C ratio is good for improving steel yield strength and impact toughness. Si; Most low-alloy high-strength steels do not require silicon alloying, but silicon is an indispensable additive element in hot-rolled ferritic-martensite multiphase steels.
Mo; molybdenum-containing steel (~0.15%Mo) has higher strength and higher toughness than conventional ferrite-pearlite steel. Nb, V, Ti; 0.05-0.15% Nb (or V, Ti) is added to low-carbon manganese steel or low-carbon manganese-molybdenum steel, which has obvious grain refinement and precipitation hardening effects. Titanium forms sulfides in steel, improving the anisotropy and cold formability of the impact absorption work.
Rare earth (RE); trace (about 0.001%) rare earth metals do not affect the strength of the steel. Its main function is desulfurization, reducing the anisotropy of toughness and preventing the layered tear of steel.
Other elements such as Ni, Cr, Cu, etc., are not very effective in solid solution hardening in microalloyed steels, and are generally controlled at lower content ranges in non-quenched and tempered steels.