30CrMnSi, is a Chinese national standard alloy structural steel grades. Uniform digital code: A24302. 
 Chemical composition 
 Mass fraction (%): C: 0.27 ~ 0.34 Si: 0.90 ~ 1.20 Mn: 0.80 ~ 1.10 
 30CrMnSi 
 Cr: 0.80 ~ 1.10 
 Mechanical Properties 
 【Size】 25mm 【sample blank] quenching heat treatment temperature (℃): 880; Coolant: Oil-tempered heating temperature (℃): 520; coolant: water, oil and mechanical properties] [tensile strength (σb / MPa ): ≧ 1080 yield point (σs / MPa): ≧ 885 Elongation (δ5 /%): ≧ 10 section shrinkage (ψ /%): ≧ 45 impact absorbed energy (Aku2 / J): ≧ 39 Brinell Hardness (HBS100/3000) (annealing or tempering state): ≦ 229 
 Key Features 
 High strength quenched and tempered structural steel. High strength and toughness, high hardenability, cold plastic deformation of the middle, cutting performance is good. A tendency to temper brittleness, poor lateral impact toughness. Welding performance is better, but thicker than 3mm should be preheated to 150 ℃, need heat treatment after welding. General conditioning before use. 
 Application examples 
 Used for the manufacture of high load, high speed of the various important parts such as gears, shafts, clutches, sprockets, wheel shafts, bushings, bolts, nuts, etc., but also for the manufacture of wear-resistant, operating temperature is not high parts, variable loads of welded components, such as high pressure blower blades, valve plate and non-corrosive pipe tubes