Alloy ХН30МДБ (ЭК77)

Designation

Name	The value
Designation GOST Cyrillic	ХН30МДБ
Designation GOST Latin	XH30MDB
Transliteration	HN30MDB
By chemical elements	CrNi30CuДBe

Name	The value
Designation GOST Cyrillic	ЭК77
Designation GOST Latin	EK77
Transliteration	EhK77
By chemical elements	-

Description

Alloy ХН30МДБ used: for the production of parts and equipment chemical and gas industry with high strength characteristics and high resistance to local corrosion for operation in highly corrosive media; pipes for nuclear power plant equipment welding wire.

Standards

Name	Code	Standards
Thermal and thermochemical treatment of metals	В04	STP 26.260.484-2004
Steel pipes and fittings to them	В62	TU 1380-001-08620133-05, TU 14-1-5378-99, TU 14-158-135-2003, TU 14-3-1711-90
Blanks. Of the workpiece. Slabs	В31	TU 14-1-1213-75, TU 14-1-4745-89, TU 14-1-4907-90, TU 14-1-5052-91
Welding and cutting metals. Soldering, riveting	В05	TU 14-1-4998-91
Sheets and strips	В33	TU 14-134-375-99
Bars and shapes	В32	TU 14-134-404-2003, TU 14-1-4056-85, TU 14-1-5156-92
Tape	В34	TU 14-406-1-99

Chemical composition

Standard	C	S	P	Mn	Cr	Si	Ni	Fe	Cu	B	Ti	Mo	Nb
TU 14-1-4745-89	≤0.02	≤0.02	≤0.02	0.5-1.8	27-29	≤0.2	29-31	Rest	0.9-1.5	0.004	≤0.1	2.8-3.5	0.05-0.2

Fe is the basis.
According to TU 14-1-4745-89 and TU 14-1-4907-90, the chemical composition is presented for the alloy grade KhN30MDB (EC77). In the finished metal, deviations from the chemical composition standards are allowed: for carbon +0.010%, for copper -0.10%, for silicon +0.10%, for chromium ± 0.20%, for other elements - in accordance with GOST 5632. The calculated content of modifiers and deoxidizers: boron, cerium, aluminum, magnesium is established by the supplier's technological instructions and their residual content in the metal is not determined by chemical analysis.

Mechanical properties

Section, mm	s_T\|s_0,2, MPa	σ_U, MPa	d₅, %	y, %
Bars hot rolled and forged at STP 26.260.484-2004. Quenching in water or air from 1050-1080 °C
	≥300	≥540	≥35	≥40
Pipe forged billet according to TU 14-1-4745-89. Quenching in water with 1090-1110 °C (exposure 40-60 min.) (longitudinal samples of the forge workpieces with a diameter of 80-100 mm)
20-25	≥305	≥590	≥35	-
Cold-rolled tubes after austenization in the state of delivery on the other 14-158-135-2003
	-	≥540	≥35	-

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

Technological properties

Name	The value
Macrostructure and pollution	The macrostructure of the metal tube blank on the other 14-1-4745-89 should not have podnasadochnogo looseness, bubbles, cracks, foreign non-metallic inclusions, crusts, visible without using the magnifying devices. The defects allowed must not exceed: - for Central porosity - 2 points; - point heterogeneity - 2 points. Contamination of metal non-metallic inclusions should not exceed average score: oxides of stroke (OS) - 1 point; - point oxides (FROM) - 2 points; - silicates fragile (CX) - 1 point; - for silicates plastic (SP) - 1 point; - for non-deformable silicates (SN) - 1 point; - the sulphides (A) - 1 point; - for nitrides and carbonitrides - 4.5 points. The macrostructure of the billet for rolling on the other 14-1-4907-90 should not have traces of shrinkage, bubbles, cracks, inclusions and delaminations.
Features of heat treatment	Products ХН30МДБ alloy subjected to quenching in water with 1070±10 °C, holding time at the heat for 2-3 minutes per mm of product thickness, but not less than 10 min.
Corrosion resistance	The alloy has high resistance to pitting and crevice corrosion, corrosion cracking, IWC welded joints, stands in the sulfate, phosphate and other harsh environments containing chlorides, fluorides and hydrogen sulfide at elevated temperatures.