25MnTiBre Structure Steel Bar

 

25MnTiBRE structural steel. The comprehensive mechanical properties of this steel better than 20CrMnTi steel, at the same time has good process performance. Steel hardenability is better, the critical quenching diameter in oil up to 17 ~ 27mm; hot and cold processing performance is good, forging temperature is wide, loose oxide, easy to clean.

 

25MnTiBRE steel are better than that of 20CrMnTi steel, and it also has good process performance. The hardenability of steel is good, the critical hardenable diameter in oil is 17 ~ 27mm; the cold and hot workability is good, the forging temperature is wide, the oxide scale is loose, and it is easy to clean. After normalizing, a more evenly distributed pearlite and ferrite structure can be obtained, and the machinability is good, the carbon distribution is gentle after carburizing, and the surface metallographic structure is normal after quenching. After rare earth is added, the low-temperature impact toughness is improved, and the notch sensitivity is reduced. The disadvantage of this steel is that the heat treatment deformation of manufactured gears is generally slightly larger than that of chrome steel gears.

 

After normalizing, more uniform distribution of pearlite and ferrite can be obtained, the machinability is good, the carbon distribution is smooth after carburizing, and the microstructure of the surface is normal after quenching. Rare earth added, low temperature impact toughness increased, notch sensitivity decreased. The disadvantage of this steel is that the heat distortion of the gear produced is slightly larger than that of a chrome steel gear.

 

Chemical Composition:

 

  • C : 0.22 ~ 0.28
  • Si : 0.20 ~ 0.45
  • Mn : 1.30 ~ 1.60
  • B : 0.0005 ~ 0.0035
  • Ti : 0.04 ~ 0.10
  • P : 0.035
  • S : 0.035
  • Cr :≤ 0.30
  • Cu ≤ 0.30
  • Ni :  0.30
  • Mo : 0.15

 

Mechanical properties:

 

  • Tensile strength (σb/MPa): ≧1380
  • Yield point (σs/MPa):-
  • Elongation after breaking (δ5/%): ≧10
  • Reduction of area (ψ/%): ≧40
  • Impact absorption work (Aku2/J): ≧47
  • Brinell hardness (HBS100/3000) (annealed or high temperature tempered state): ≦229

 

Heat treatment:

 

  1. The first quenching heating temperature (℃): 860; coolant: oil
  2. The second quenching heating temperature (℃):-
  3. Tempering heating temperature (℃): 200; Coolant: water, air


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