What is the material of B7 What is the material of B7B2OA

The B7 U.S. brand is close to the domestic 42CrMoa material, which contains different MN elements, and should be 40CRmnMoa.

42CrMOA is an ultra-high-strength steel, with high strength and toughness, good hardenability, no obvious tempering brittleness, high fatigue limit and multiple impact resistance after quenching and tempering treatment, and good low-temperature impact toughness. The steel is suitable for manufacturing large and medium-sized plastic molds that require a certain strength and toughness.

42CRMO, a steel for high-strength bolts, requires high strength, good resistance to low temperature brittleness, and strict grain size. Fine-grained strengthening and improved low-temperature properties of steel are achieved by alloying CR and MO, controlling carbon content and residual elements in the steel, and controlling the second phase in the rolling control steel. The test shows that the actual grain size of the steel is 6 8 grades, all kinds of inclusions are below the grade, AKV reaches 27J (-100), and the mechanical properties fully meet the requirements of users.

ASTM A193 B7 belongs to the American standard alloy structural steel for high-temperature bolts, and the executive standard: ASTM A193 A193M-2017

ASTM A193 B7 steel is an ultra-high strength steel, which has high strength and toughness, good hardenability, no obvious tempering brittleness, high fatigue limit and multiple impact resistance after quenching and tempering treatment, and good low-temperature impact toughness. ASTM A193 B7 steel is suitable for the manufacture of large and medium-sized plastic molds and high-strength, high-temperature bolts and nuts that require a certain strength and toughness.

The chemical composition of ASTM A193 B7 is shown in the following figure:

Some say it's 35crmo. However, my unit thinks so, the chemical composition of B7 and 42CrMo is not much different, just a little different from Mn, but the performance level is almost the same, because B7 is cheaper than 42CrMo, so without affecting the performance level, B7 is used instead.

B7 steel refers to 40 chromium-manganese-molybdenum (40CrMnmo), which is a steel material.

40CRMNMO, executive standard: GB T3077-1999 unified digital code: A34402. Delivered in heat-treated (normalized, annealed or high-temperature tempered) or without heat-treated, the delivery status should be indicated in the contract.

Mass fraction of chemical composition (%)

c：si：mn：cr：mo：

B7 is the ASTM A193 A193M "Alloy Steel and Stainless Steel Bolt Materials at High Temperature" standard applicable to alloy steel and stainless steel bolt materials on pressure vessels, valves, flanges and fittings using Li Fanzhao at high temperatures. Which rent A193 B7 (or A193 B7M) mechanical properties standard grade, the corresponding minimum tensile strength is the car; The minimum yield strength is; The elongation is 16(18); The maximum hardness is HRC35 (HB235), material: chromium-molybdenum alloy steel, the American grade is selected, which is equivalent to 40CRMO in China.

This is ASTM

A193 A193M "Alloy steel at high temperatures.

and stainless steel bolt materials" standard for alloy steel and stainless steel bolt materials on pressure vessels, valves, flanges and fittings used at high temperatures. a193

B7 (or A193

b7m) standard grade of mechanical properties, corresponding to the minimum tensile strength.

Be; Minimum yield strength.

Be; The elongation is 16(18); The maximum hardness B7 is HB321 and B7M is HB235

The chemical composition of B7 and B7M is the same, and both are equivalent to the domestic 42CrMoA