GB/T 5615-1985 Names, definitions and codes of heat treatment conditions of steel castings

This standard specifies the names, definitions and codes of commonly used heat treatment conditions for steel castings. GB/T 5615-1985 Names, definitions and codes of heat treatment conditions for steel castings GB/T5615-1985 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Names, definitions and symbols for heat treatment tempersof steel castings
This standard specifies the names, definitions and symbols for heat treatment tempersof steel castings. 1. Representation rules
UDC 621.741. 4
GB5615—85bzxZ.net
1.1 The names and definitions of heat treatment tempers of steel castings are determined according to different heat treatment processes. 1.2 The codes of heat treatment tempers of steel castings are represented by the first capital letter of the Latin alphabet and the Chinese phonetic alphabet. When the code letters of two or more names are the same, a lowercase letter can be added after them to distinguish them. The code is placed in parentheses "()". It is marked after the cast steel grade. 1.3 When a certain steel casting undergoes more than two heat treatments, the state codes can be marked in sequence according to the order of the processes, and each state code is separated by a small dot ".".
2 Common heat treatment state names and definitions of steel castings 2.1 As-cast: The state of the casting without any heat treatment. 2.2 Annealed: According to different steel grades and purposes, the casting is heated to an appropriate temperature above the critical point Ac3, or between Ac, and Acom, or below Ac, and then slowly cooled after being kept warm. To obtain a structure close to the equilibrium state. 2.3 Stress removal annealing: In order to remove the stress caused by casting, welding and other processing, the casting is heated to a certain temperature, kept warm for an appropriate time, and then slowly cooled. 2.4 Homogenization annealing: The casting is heated to an appropriate temperature below the solidus, kept warm for a long time, and then slowly cooled. In order to achieve the purpose of chemical composition homogeneity.
2.5 Stabilization treatment state: Austenitic stainless steel castings containing titanium and saw are heated to an appropriate temperature lower than the complete annealing temperature, and after heat preservation, the carbon in the steel is fully combined with titanium and saw to form stable carbides. 2.6 Normalizing state: According to different steel types, the casting is heated to an appropriate temperature above the critical point (Ac: for hypoeutectoid steel and Ac, for hypereutectoid steel), and the steel is austenitized after heat preservation, and then air-cooled to adjust the structure and improve the mechanical properties. 2.7 Quenching state: According to different steel types, the casting is heated to an appropriate temperature above the critical point (Ac3 for hypoeutectoid steel and Ac, for hypereutectoid steel), and then quickly cooled after heat preservation. An unstable structure is obtained, generally martensite. 2.8 Tempering state: The casting after quenching or normalizing is heated to an appropriate temperature below Ac, (for some steel types, above Ac,), and then cooled at an appropriate rate after heat preservation.
2.9 Precipitation hardening state: By The solute segregation area precipitated in the supersaturated solid solution, or the second phase particles precipitated therefrom are dispersed in the matrix and cause hardening.
2.10 Solution heat treatment state: The casting is heated to the high temperature single-phase area, and after heat preservation, the excess phase is fully dissolved in the solid solution to form a single-phase solid solution, and then it is quickly cooled to keep these dissolved components in the solid solution. - Hypereutectoid steel, the temperature at which the carburized body is completely dissolved into the austenite during the heating process. Note: Acom -
- The temperature at which austenite begins to form during the heating process. Acr -
Issued by the National Bureau of Standards on November 25, 1985
Implemented on August 1, 1986
GB 5615-85
--The temperature at which ferrite completely transforms into austenite during the heating process. 3 Codes for commonly used heat treatment states of steel castings
Z--Casting state
T--Annealing state
Q--Stress relief annealing state
J--Homogenization annealing state
W--Stabilization treatment state
Normalizing state
Quenching state
H---Tempering state
Ch--Precipitation hardening state
Solution heat treatment state
ZG19Mn12SiZ(Zh·H)
Tempering code
Normalizing code
Cast steel grade
ZG0Cr13Ni4 Mo(Zh-HH)
Secondary tempering code
First tempering code
Normalizing code
Cast steel grade
Additional instructions:
This standard is proposed by the Ministry of Machinery Industry of the People's Republic of China. This standard is drafted by the Shenyang Foundry Research Institute of the Ministry of Machinery Industry. The main drafters of this standard are Sun Yujiu and Jiang Jiahui.
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