30Mn5 alloy structural steel
30Mn5 Overview
30Mn5 the German brands, Chinese brands rather 30Mn2. High-quality structural steel, high carbon content than low-carbon steel, are in the low carbon content. Because carbon than the lower, toughness, wear resistance, but the surface is not enough, so often as a surface hardening treatment such as carburizing, nitriding treatment. General for surface hardening treatment before quenching, in order to obtain better mechanical properties. 30Mn5 after quenching with high strength, toughness and abrasion resistance, static strength and fatigue strength is good. 30Mn5 important for a small section of fasteners can be used as frame rails, transmission gears, shafts, bolts and cold heading quality pieces of a larger cross-section of the tune, and mining machinery, the center of carburized parts requiring high strength, such as crane and rear axle journal and so on.
Feature
30Mn5 after quenching with high strength, toughness and abrasion resistance, static strength and fatigue strength is good. 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.
Use
Important for a small section of the fastener can be used as frame rails, transmission gears, shafts, bolts and cold heading quality pieces of a larger cross-section of the tune, and mining machinery, the center of carburized parts requiring high strength, such as cranes rear axle and journal, etc. Used as a connecting rod, spindle, crank, axle, lever, fan parts, cold forging diameter less than 15MM bolts to withstand a variety of important high stress mechanical parts. In the production of small cross section (diameter less than 20MM) parts can be replaced by 40Cr steel. 30Mn5 (1.1170) alloy structural steel
Physical properties
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
Mechanical properties
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)
Hardness: ≤ 207HB
Sample size: Sample size is 25mm rough
Standard heat treatment and microstructure
Standard heat treatment: quenching 840 ℃, water-cooled; tempering 500 ℃, water-cooled.
Delivery status: to heat treatment (normalizing, annealing, or tempering) or heat treatment delivery, delivery status should be indicated in the contract.
