38CrMoAl is an alloy structural steel characterized by high aluminum composition, which is generally used after quenching and nitriding.After nitriding, 38CrMoAl has high surface hardness, wear resistance and fatigue strength, and has [SCALE STEEL]good heat resistance and corrosion.
The characteristic of 38CrMoAl nitriding is that the speed is fast and the depth of nitriding layer can be obtained. However, the brittleness of the nitriding layer is relatively large, so it is not suitable for making parts that bear great impact.
STANDARD GB/T 3077 SAE 6470 JIS G4053 DIN EN 10085
GRADE 38CrMoAl 135 Mod
UNS K24065 SACM645
C 0.35~0.42 0.38~0.43 0.40~0.50 0.38~0.45
Si 0.20~0.45 0.20~0.40 0.15~0.50 ≤0.40
Mn 0.30~0.60 0.50~0.80[SCALE STEEL] ≤0.60 0.40~0.70
P ≤0.035 ≤0.025 ≤0.030 ≤0.025
S ≤0.035 ≤0.025 ≤0.030 ≤0.035
Cr 1.35~1.65 1.40~1.80 1.30~1.70 1.50~1.80
Mo 0.15~0.25 0.30~0.40 0.15~0.35 0.20~0.35
Al 0.70~1.10 0.95~1.30 0.70~1.20 0.80~1.20
TYPES TEM ℃ COOLING HRC
ANNEALING 840~870 FURNACE COOLING ≤229HB
NORMALIZING 930~970 AIR COOLING --
QUENCHING 940 OIL ＞56
TEMPERING 150~200 WATER OR OIL[SCALE STEEL] 51~56
300~400 WATER OR OIL 45~51
500~550 WATER OR OIL 35~39
600~650 WATER OR OIL 28~31
The process flow of nitriding parts is generally: forging → normalizing (annealing) → rough machining → tempering and tempering → finishing [SCALE STEEL]machining → de-stress → fine grinding → nitriding → fine grinding → assembly.
The purpose of 38CrMoAl nitriding treatment is mainly for wear resistance.After nitriding, its hardness is as high as HV800, the hardened layer [SCALE STEEL]can reach 0.30mm ~ 0.5mm.
38CrMoAl is mainly used in the manufacture of parts with precise size, requiring high wear resistance and fatigue strength, and not subjected to large impact load, such as cylinder liner, bottom sleeve, gear, bolts, shaft and rotor, etc.
In addition, because Al and Cr elements can form a dense passivation film on the surface of steel, so 38CrMoAl is also a kind of seawater [SCALE STEEL]corrosion resistant steel.Its seamless steel pipe is the most ideal pipeline and processing material for transporting water, oil and gas and seawater containing medium in coastal power plants, coastal oil fields, coastal natural gas and petrochemical plants.