Steel 38KHGNM

Designation

Name The value
Designation GOST Cyrillic 38ХГНМ
Designation GOST Latin 38XGHM
Transliteration 38HGNM
By chemical elements 38CrMnНMo

Description

38KHGNM steel is used: for the manufacture of products by cold extrusion and upsetting and hot-rolled (rolled, wire rod) for the manufacture and calibrated with special surface finish rolling and wire used for the manufacture of special fasteners, shafts, axles and other critical parts of the mining and metallurgical and oil-processing equipment, requirements of increased strength.

Standards

Name Code Standards
Bars and shapes В32 GOST 10702-78, TU 14-1-1866-75
Blanks. Of the workpiece. Slabs В31 TU 14-1-993-74

Chemical composition

Standard C S P Mn Cr Si Ni Fe Mo
TU 14-1-993-74 0.37-0.43 ≤0.035 ≤0.035 0.7-1 0.4-0.6 0.17-0.37 0.4-0.7 Rest 0.15-0.25
Fe is the basis.
According to TU 14-1-993-74 the chemical composition is given for steel grade 38ХГНМ. Permissible deviations from the norms for chemical composition: carbon ± 0.010%, manganese, chromium, molybdenum and silicon ± 0.020% each, nickel ± 0.030%, sulfur and phosphorus ± 0.0050% each.

Mechanical properties

Section, mm σU, MPa y, %
Steel calibrated and calibrated with special surface finish after spheroidizing annealing
≤690 ≥60

Description mechanical marks

Name Description
σU Limit short-term strength
y The relative narrowing

Physical characteristics

Temperature r, kg/m3
20 7800

A description of the physical symbols

Name Description
Е The normal elasticity modulus
l Coefficient of thermal conductivity

Technological properties

Name The value
Weldability Difficult weldability. Method of welding: SMAW. Necessary preheating and subsequent heat treatment.
Склонность к отпускной хрупкости Inclined.
The temperature of forging The beginning of 1200 °C, the end of the 800°C. the cross Sections up to 250 mm are cooled in air, 251-350 mm - in the pit.
Flock-sensitive sensitivity Sensitive.
Macrostructure and pollution The macrostructure of the steel when checking on the etched transverse templeto should not have shrinkage looseness, blistering, delamination, cracks, inclusions and placenow.
Microstructure Harvesting on the other 14-1-993-74 should be supplied with a grain size not larger than 5 rooms, allowed the presence of small quantities of grains the 3. Depth bezoperatsionnogo layer in the workpiece (ferrite + transition zone) must not exceed 1.5% per side.