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GB/T 39191-2020: PDF in English (GBT 39191-2020)
GB/T 39191-2020
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 25.200
J 36
Heat Treatment for Stainless Steel and Heat Resistant
Steel Parts
ISSUED ON: OCTOBER 11, 2020
IMPLEMENTED ON: MAY 01, 2021
Issued by: State Administration for Market Regulation;
Standardization Administration of PRC.
Table of Contents
Foreword ... 3
1 Scope ... 4
2 Normative References ... 4
3 Terms and Definitions ... 5
4 Classification of Common Stainless Steel and Heat-Resistant Steel ... 5
5 Heat Treatment Method and Process ... 7
6 Equipment ... 15
7 Process ... 16
8 Quality Control and Inspection ... 20
9 Safety and Environmental Health ... 21
10 Requirements for Energy Consumption ... 21
Heat Treatment for Stainless Steel and Heat Resistant
Steel Parts
1 Scope
This Standard specifies requirements for common materials, heat treatment methods
and processes, heat treatment equipment, processes, quality control and inspection,
safety and environmental health, energy consumption, etc. of stainless steel and heat-
resistant steel parts.
This Standard is applicable to the heat treatment of stainless steel and heat-resistant
steel parts used in the equipment manufacturing industry. Other industries can be
implemented by reference of it.
2 Normative References
The following documents are essential to the application of this document. For the
dated documents, only the versions with the dates indicated are applicable to this
document; for the undated documents, only the latest version (including all the
amendments) is applicable to this document.
GB/T 7232 Terminology of Metal Heat Treatment
GB/T 9452 Testing Method for Work Zone of Heat Treatment Furnace
GB 15735 Requirements for the Safety and Health in Production Process of Metal
Heat Treatment
GB/T 17358 Power Consumption Measurement and Testing in Heat Treating
Production
GB/T 20878 Stainless and Heat-Resisting Steels - Designation and Chemical
Composition
GB/T 27946 Limited Value of Hazardous Substance in the Air of Heat Treatment
Working Place
GB/T 30822 Environmental Protection Technical Requirements for Heat Treatment
Industry
GB/T 30825 Pyrometry for Heat Treatment
GB/T 32529 Technical Requirement of Cleaning Liquid Waste Recycling and
Emissions for Heat Treatment
GB/T 32541 Quality Control System for Heat Treatment
JB/T 10457 Technological Requirements of Liquid Quenching Apparatus
3 Terms and Definitions
For the purpose of this document, the terms and definitions given in GB/T 7232, GB/T
20878 and the following apply.
3.1 Heat-treatable steel
Steel whose strength can be significantly improved by proper heat treatment.
3.2 Non-heat-treatable steel
Steel whose strength can’t be significantly improved by proper heat treatment.
3.3 Adjusting heating treatment
Solution treatment that is performed to change the martensite transformation point of
precipitation hardening stainless steel.
3.4 Stabilizing treatment
Heat treatment that is performed to improve the corrosion resistance and the stability
in shape or size of steel.
NOTE: The stabilizing treatment includes stabilization annealing and stabilization tempering
treatment.
4 Classification of Common Stainless Steel and Heat-
Resistant Steel
Stainless steel and heat-resistant steel are divided into non-heat-treatable steel and
heat-treatable steel according to the heat treatment; and are divided into austenitic,
ferritic, martensitic, austenite-ferritic and precipitation hardening stainless steels
according to the microstructure. The classification of common stainless steel and heat-
resistant steel and the comparison between new and old designations are shown in
Table 1. The chemical composition of steel in Table 1 shall comply with the provisions
of GB/T 20878.
5.2.1.1 For the workpieces that require to eliminate the processing stress, reduce the
hardness and increase the plasticity, as well as to improve the cutting performance of
steel and obtain the best structure, annealing, two-stage annealing or multi-stage
annealing may be carried out.
5.2.1.2 For workpieces that require improvement of the original structure, the
normalizing + high temperature tempering of preparing heat treatment may be carried
out.
5.2.1.3 For the precipitation hardening stainless steel workpieces for important
purposes, they shall be dehydrogenated to eliminate the effects of hydrogen
embrittlement.
5.2.2 Final heat treatment
5.2.2.1 For workpieces that require to improve strength, hardness and corrosion
resistance, the quenching + low temperature tempering shall be carried out.
5.2.2.2 For workpieces that require high strength and elastic limit, and do not require
high corrosion resistance, the quenching + medium temperature tempering shall be
carried out.
5.2.2.3 For workpieces that require good comprehensive mechanical properties and
certain corrosion resistance, quenching + high temperature tempering shall be carried
out.
5.2.2.4 For precipitation hardening stainless steel workpieces that require good
comprehensive mechanical properties and corrosion resistance, adjusting heat
treatment such as solid solution + aging, solid solution + cold treatment or cold
deformation + aging may be carried out.
5.2.3 Re-heat treatment
5.2.3.1 When the mechanical properties of stainless steel or heat-resistant steel parts
do not meet the requirements after heat treatment, re-heat treatment may be
performed. However, the number of repeated quenching or solution treatments shall
not exceed twice. Complementary tempering of the workpiece is not regarded as a re-
heat treatment.
5.2.3.2 The martensitic stainless steel and heat-resistant steel in the quenched state
or after low temperature tempering shall be preheated, annealed or high temperature
tempered before repeated quenching.
5.3 Fusion welding assembly
5.3.1 For the fusion welding assembly that is composed of heat-treatable stainless
6 Equipment
6.1 Heating equipment
6.1.1 Stainless-steel and heat-resistant steel workpieces may be heated by air
resistance furnace, protective atmosphere furnace, vacuum furnace, etc. For finished
workpieces, thin-walled workpieces, bolts, etc., it shall be heated in a protective
atmosphere furnace or a vacuum furnace. The quenching (solution) treatment of
precipitation hardening stainless-steel finished parts shall use a vacuum furnace.
6.1.2 The temperature of the effective heating zone of the heating furnace shall be
measured according to the method specified in GB/T 9452. The heating furnace for
quenching and tempering shall be no lower than the Class-III furnace; and the heating
furnace for the aging treatment of precipitation hardening stainless-steel and heat-
resistant steel shall be no lower than the Class-II furnace. The temperature uniformity
inspection cycle shall comply with the provisions of GB/T 30825 and GB/T 32541.
6.1.3 The temperature monitoring system of the heating furnace shall comply with the
relevant provisions of GB/T 32541; and each heating zone shall be equipped with
temperature instruments for automatic control, recording and alarm.
6.1.4 The instrument type and system accuracy requirements and calibration period of
the heating furnace shall comply with the relevant provisions of GB/T 32541.
6.1.5 The atmosphere in the protective atmosphere heating furnace shall be adjustable
and controlled. When the protective atmosphere enters the heating furnace, it shall not
directly scour the workpiece and adversely affect the workpiece. When the temperature
is lower than 770°C, nitrogen may be used as a protective atmosphere; but nitrogen
decomposed from ammonia shall not be used as a protective atmosphere. When the
temperature is higher than 770°C, nitrogen shall not be used as a protective
atmosphere for annealing or solution treatment.
6.1.6 The pressure rise rate of the vacuum furnace shall be less than 1.33Pa/h, when
the vacuum degree is higher than 0.13Pa; the vacuum degree and atmosphere in the
furnace shall be adjusted according to the requirements of the heat treatment process.
6.2 Cooling equipment
6.2.1 The cooling equipment shall comply with the provisions of JB/T 10457.
6.2.2 The volume of the cooling device shall ensure sufficient cooling capacity under
continuous production conditions.
6.2.3 The cooling device shall be equipped with a cooling cycle system and a stirring
device (compressed air stirring is prohibited); and a heating device shall be equipped
7.2.5 Clean up by sandblasting or shot peening.
7.3 Furnace loading
7.3.1 The workpiece shall be placed in the effective heating zone of the heating furnace.
7.3.2 Special fixtures shall be used for workpieces that are prone to deformation during
heat treatment.
7.3.3 The material pan, material basket or fixture shall be made of stainless steel or
heat-resistant steel.
7.3.4 The temperature of the furnace loading shall not exceed the specified tempering
temperature during the tempering period.
7.4 Heating
7.4.1 For workpieces with complex shapes or sharp changes in cross-sections and
large effective thicknesses, the heating rate shall be controlled; and preheating shall
be carried out, if necessary, to reduce deformation and prevent cracking. The
preheating methods include:
a) One-stage preheating: 800°C ~850°C;
b) Two-stage preheating: 500°C ~650°C and 800°C ~850°C.
7.4.2 There shall be enough heat preservation time for the heating of the workpiece.
The start time of heat preservation shall be calculated from the last recording
thermocouple in the work area reaching the lower limit of the setting temperature.
7.4.3 The length of the heat preservation time may be adjusted according to the shape
and size of the parts, heating temperature, heating medium, heating method, furnace
loading method, and furnace loading volume, etc. For the workpieces after preheating,
the heat preservation time may be appropriately shortened.
In general, the methods for determining the heat preservation time include:
a) In the case of single-layer bulk, the heat preservation time shall be calculated
according to the effective thickness or conditional thickness of the workpiece,
see Table 6. While the effective thickness or conditional thickness is the actual
thickness multiplied by the shape factor of the workpiece, see Table 7.
b) In the case of dense stacking, the heat preservation time shall be calculated
according to the maximum stacking effective thickness or the conditional
thickness of the workpiece. When the furnace load has a greater influence on
the heat transfer, it is allowed to increase the heat preservation time according
to the furnace loading coefficient of the workpiece; that is, the heat preservation
7.5.2 After the martensitic stainless steel and heat-resistant steel is quenched and
cooled off to the room temperature, they may be cleaned, cold treated or tempered.
7.5.3 After the martensitic stainless steel and heat-resistant steel workpieces are
quenched, they shall be tempered in time; and the time interval shall not exceed 4h.
7.5.4 For fusion welded assemblies that are composed of martensitic stainless steel
and heat-resistant steel, the time interval between welding and subsequent heat
treatment shall not exceed 4h.
7.6 Calibration
7.6.1 The workpiece shall be calibrated under static load conditions; and it is generally
not suitable to knock locally.
7.6.2 After the martensitic stainless steel and heat-resistant steel workpieces are
calibrated, they shall be subjected to stress-relief annealing at a temperature lower
than the original tempering temperature.
7.6.3 When tempering workpieces with complex shapes or strict size requirements,
use a shaping fixture and tempering for calibration.
7.6.4 After the austenitic stainless-steel workpiece is calibrated, perform stress-relief
annealing at a temperature below 300°C.
8 Quality Control and Inspection
8.1 The quality control requirements of the heat treatment process shall comply with
the provisions of GB/T 32541.
8.2 The workpiece shall be inspected according to the items and requirements
specified in the corresponding technical documents.
8.3 The original record of heat treatment shall be filled in as required and kept properly.
8.4 According to requirements, a quality report may be issued for each batch or furnace.
The content of the report includes but not limited to:
--- The name and drawing number of the workpiece;
--- Technical requirements of the product;
--- The material designation of the workpiece;
--- single piece weight and quantity;
......

BASIC DATA
Standard ID GB/T 39191-2020 (GB/T39191-2020)
Description (Translated English) Heat treatment for stainless steel and heat resistant steel parts
Sector / Industry National Standard (Recommended)
Classification of Chinese Standard J36
Classification of International Standard 25.200
Word Count Estimation 18,141
Date of Issue 2020-10-11
Date of Implementation 2021-05-01
Drafting Organization Beijing Mechanical and Electrical Research Institute Co., Ltd., Hefei Shihua Pipe Fittings Co., Ltd., Zhuhai Gree Electric Appliance Co., Ltd., Zhuzhou CRRC Tianli Forging Co., Ltd., Guizhou Aerospace Science and Technology Development Co., Ltd., Tianjin Heat Treatment Institute Co., Ltd., Beijing Xinli Machinery Co., Ltd., Xi'an Flat Heat Treatment Co., Ltd., Changzhou New District Hehai Heat Treatment Engineering Co., Ltd.
Administrative Organization National Heat Treatment Standardization Technical Committee (SAC/TC 75)
Regulation (derived from) National Standard Announcement No. 21 of 2020
Proposing organization National Heat Treatment Standardization Technical Committee (SAC/TC 75)
Issuing agency(ies) State Administration for Market Regulation, National Standardization Administration