30Mn2 alloy structural steel

 

   Cold plastic deformation of the middle, cutting and welding can be acceptable, but will be required before welding preheat parts to 200 ℃ or more. Drawing and cold forging and heat treatment process with good performance, high hardenability, quenching in oil, the critical diameter of 6.5 ~ 18mm, deformation hardening is small, but there is overheating, decarburization sensitivity and temper brittleness. The steel quenched after a high strength, toughness and wear resistance, and static strength and fatigue strength are also good.

35Mn2
Outline
30Mn2, alloy structural steel.

Standard: GB / T 3077-1988

    Chemical composition:

  Carbon C: 0.27 ~ 0.34

Si Si: 0.17 ~ 0.37

Manganese Mn: 1.40 ~ 1.80

Sulfur S: to allow the residual content of ≤ 0.35

Phosphorus P: allow the residual content of ≤ 0.35

Chromium Cr: allow the residual content of ≤ 0.30

Ni: to allow the residual content of ≤ 0.30

Copper Cu: to allow the residual content of ≤ 0.30
Alloy structural steel (6) 30mn2 representation
① steel beginning of the two numbers indicate the carbon content of steel, the average carbon content of the very few that, as 40Cr, 25Cr2MoVA alloy tube.

② the main alloying elements in steel, in addition to individual micro-alloying elements, the general said to a few percent. When the average alloy content <1.5%, the steel elements generally marked only symbols, but not marked content, but prone to cause confusion in those special 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%, 0.9-1.2% for the latter, all the remaining ingredients the same. When the average content of alloying elements ≥ 1.5%, ≥ 2.5%, ≥ 3.5% ... ... when, after the element symbol should be marked content, can be expressed as the corresponding 2,3,4 ... etc. For example 18Cr2Ni4WA.

 ③ vanadium steel V, Ti Ti, Al AL, boron B, and other rare earth RE alloying elements, are micro-alloying elements, although the content is very low, should bid out in steel. For example 20MnVB steel. To 0.07-0.12% vanadium, boron is 0.001-0.005%.

 ④ High quality steel should be added in the last steel "A", as distinct from the general high quality steel.

 ⑤ special purpose alloy structural steel, steel, known (or suffix) represents the symbol of the use of steel. Case [(OD - Wall Thickness) * Thickness] * 0.02466 = kg / m (the weight per meter)
Mechanical properties
Blank sample size (mm): 25

Heat treatment: the first quenching temperature (℃): 840; coolant: water

Second quenching temperature (℃): - tempering heating temperature (℃): 500; coolant: water

Tensile strength σb (MPa): ≥ 785 (80)

  Yield strength σs (MPa): ≥ 635 (65)

Elongation δ5 (%): ≥ 12

  Reduction of area ψ (%): ≥ 45

  Impact energy Akv (J): ≥ 63

  Impact toughness αkv (J/cm2): ≥ 78 (8)

Brinell hardness (HBS100/3000) (annealing or tempering condition): ≦ 207

Delivery status: to heat treatment (normalizing, annealing, or tempering) or heat treatment