Alloy round bar (30Mn2) 



 Standard: GB / T 3077-1988 



 Chemical Composition (%) 



 C: 0.27 ~ 0.34 Si: 0.17 ~ 0.37 Mn: 1.40 ~ 1.80 S ≤ 0.35 P ≤ 0.35 Cr ≤ 0.30 Ni ≤ 0.30 

 Cu ≤ 0.30 



 Mechanical properties 
 Sample rough dimensions (mm): 25 

 Heat treatment: 

 First quenching temperature (° C): 840; coolant: water 

 Second quenching temperature (° C): - 

 Tempering the heating temperature (° C): 500; coolant: water 

 Tensile strength σb (MPa): ≥ 785 (80) 

 Yield strength σs (MPa): ≥ 635 (65) 

 Elongation δ5 (%): ≥ 12 

 Section shrinkage ψ (%): ≥ 45 

 Impact energy Akv (J): ≥ 63 

 The impact toughness values ??αkv (J/cm2): ≥ 78 (8) 

 Brinell hardness (HBS100/3000) (annealing or high temperature tempered condition): ≤ 207 





 Steel beginning of the two numbers indicate the carbon content of steel, the average carbon content of the very few, such as 40Cr, 25Cr2MoVA alloy tube 

 The major alloying elements in steel, in addition to the individual micro-alloying elements, generally a few percent. When the average alloy content <1.5%, steel, generally mark the element symbol not indicate the content and prone to cause confusion, but in exceptional circumstances, after the element symbol can also be marked with the number "1", such as steel "12CrMoV" and "12Cr1MoV", the former chromium content of 0.4-0.6% and 0.9-1.2%, and the remaining ingredients are all the same. When the average content of alloying elements ≥ 1.5% ≥ 2.5% ≥ 3.5% ... in the back of the element symbols should be marked content, can be said that the corresponding 2,3,4 ...... and so on. For example 18Cr2Ni4WA. 

 Vanadium V steel, titanium Ti, aluminum AL, boron B, rare earth RE alloying elements are micro-alloying elements, although the content is very low, should still be marked in the steel. 20MnVB steel. Vanadium 0.07-0.12%, 0.001-0.005% boron. 

 High quality steel in the steel and finally add the "A", to distinguish them from the general high quality steel. 

 Purpose-alloy structural steel, steel, dubbed (or suffix) on behalf of the steel use the symbol. Case 

 [(OD - Wall Thickness) * Wall thickness] * 0.02466 = kg / m (the weight per meter) 



 Delivery status: to heat treatment (normalizing, annealing, or high-temperature tempering) or heat treatment state of delivery, the delivery status should be indicated in the contract.