04Х25Н5М2 steel is used: for the manufacture of equipment for chemical industry, organic synthesis and production of sulfuric acid; equipment for pulp and paper industry; parts and welded structures operating in environments of increased aggressiveness: acetate, sulfate, phosphate environments.

Note

Austenite corrosion resistant steel-ferritic class.

Standards

Name	Code	Standards
Thermal and thermochemical treatment of metals	В04	STP 26.260.484-2004
Blanks. Of the workpiece. Slabs	В31	TU 14-1-4582-89, TU 14-1-2639-79

Chemical composition

Standard	C	S	P	Mn	Cr	Si	Ni	Fe	Cu	Mo
TU 14-1-2639-79	≤0.04	≤0.025	≤0.035	1-2	24.5-26.5	≤0.4	5-6	Rest	≤0.3	1.7-2.5

Fe is the basis.
According to TU 14-1-2639-79, the chemical composition is presented for steel grade 04X25N5M2 (DI62). Deviations from the established norms of chemical composition are allowed: for silicon +0.10%, for nickel ± 0.20%. The content of residual elements in accordance with GOST 5632. At the request of the consumer, the steel is alloyed with niobium. The content of niobium should be within 10 · С ÷ 0,60%. Steel in this case has the designation 04X25N5M2B.

Mechanical properties

Section, mm	s_T\|s_0,2, MPa	σ_U, MPa	d₅, %	y, %	KCU, kJ/m²
Bullion on the other 14-1-2639-79. The samples along the grain. Annealing in air 1000-1040 °C, air cooling
	≥490	≥640	≥20	≥50	≥980
Bars hot rolled and forged at STP 26.260.484-2004. Quenching in water or air 1000-1040 °C + Vacation at 350-400 °C, air cooling
	≥500	≥650	≥20	≥50	≥980

Description mechanical marks

Name	Description
s_T\|s_0,2	Yield strength or limit of proportionality with a tolerance for residual deformation of 0.2%
σ_U	Limit short-term strength
d₅	Elongation after rupture
y	The relative narrowing
KCU	Toughness

Technological properties

Name	The value
Macrostructure and pollution	In the macrostructure of steel on the other 14-1-2639-79 should be no traces of shrinkage, bubbles, cracking, and gross foreign metal and slag inclusions visible to the naked eye. On the surface of ingots shall not be longitudinal cracks, slag inclusions with a depth of more than 5 mm and mesh height of more than 3 mm. the Defects must be removed by cutting or Stripping. The ratio of the width to the depth of cutting must be not less than 6. The depth of the cutting or Stripping shall not exceed 10% of the sides of the ingot.
Features of heat treatment	Steel products to eliminate the tendency to intergranular corrosion are subjected to hardening regime: heating up to 1020±20 °C, cooling in water, excluding products with a cross section up to 10mm, which cooled in air. The holding time at the heating for hardening to products with a wall thickness up to 10 mm - 30 min, over 10 mm — 20 min + 1 min per 1 mm maximum thickness. Vacation at 350-400 °C, exposure 2 h. two-hour exposure can be applied to the partial withdrawal and redistribution of residual stresses after avtomatizovani. Steel 04Х25Н5М2 at 700-900 °C is prone to embrittlement in connection with the formation of Sigma phase, therefore, heating and cooling in this temperature range must be performed with maximum speed. Products austenite-ferritic steels do not require heat treatment after welding.
Corrosion resistance	04Х25Н5М2 steel has higher corrosion resistance than steel 08KH21N6M2T, including against pitting corrosion, and its strength is much higher. Steel resistant to stress corrosion cracking (CU).

Steel 04Х25Н5М2 (ДИ62)

Designation

Description