GB/T 31303-2014 English PDF (GBT31303-2014)

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GB/T 31303-2014: Austenitic-Ferritic duplex stainless steel bars
GB/T 31303-2014
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 77.140.20
H 44
Austenitic-Ferritic Duplex Stainless Steel Bars
ISSUED ON: DECEMBER 5, 2014
IMPLEMENTED ON: SEPTEMBER 1, 2015
Issued by: General Administration of Quality Supervision, Inspection and
Quarantine;
Standardization Administration of the People’s Republic of China.
Table of Contents
Foreword ... 3
1 Scope ... 4
2 Normative References ... 4
3 Ordering Contents ... 7
4 Classification and Code ... 8
5 Dimensions, Shape, Weight and Allowable Deviations ... 8
6 Technical Requirements ... 9
7 Test Methods ... 15
8 Inspection Rules ... 16
9 Packaging, Marking and Quality Certificate ... 16
Appendix A (Informative) Recommended Heat Treatment System of Austenitic-Ferritic
Duplex Stainless Steel Bars ... 17
Appendix B (Informative) Comparison of Designations between this Standard and
Other Similar Standards ... 18
Bibliography ... 21
Austenitic-Ferritic Duplex Stainless Steel Bars
1 Scope
This Standard specifies the classification and code, size, shape, weight and allowable deviation,
technical requirements, test methods, inspection rules, packaging, marking, and quality
certificates of austenitic-ferritic duplex stainless steel bars.
This Standard applies to rolled or forged austenitic-ferritic duplex stainless steel bars with
dimensions (diameter, side length, thickness or distance of the opposite side) not exceeding
250mm. Austenitic-ferritic duplex stainless steel bars (hereinafter referred to as steel bars) with
dimensions (diameter, side length, thickness or distance of the opposite side) greater than
250mm can also be supplied upon negotiation between the supplier and the purchaser.
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 222 Permissible tolerances for chemical composition of steel products
GB/T 223.3 Methods for chemical analysis of iron, steel and alloy - The diantipyryl
methane phosphomolybdate gravimetric method for the determination of phosphorus
content
GB/T 223.4 Alloyed steel - Determination of manganese content - Potentiometric or visual
titration method
GB/T 223.5 Steel and iron - Determination of acid-soluble silicon and total silicon content
- Reduced molybdosilicate spectrophotometric method
GB/T 223.11 Iron, Steel and Alloy - Determination of Chromium Content - Visual Titration
or Potentiometric Titration Method
GB/T 223.16 Methods for Chemical Analysis of Iron, Steel and Alloy - The Chromotropic
Acid Photometric Method for the Determination of Titanium Content
GB/T 223.17 Methods for chemical analysis of iron steel and alloy - The
diantipyrylmethane photometric method for the determination of titanium content
GB/T 2101 General provisions on acceptance, package, marking and quality certificate for
profile steel
GB/T 2975 Steel and Steel Products - Location and Preparation of Test Pieces for
Mechanical Testing
GB/T 4162 Forged and Rolled Steel Bars - Method for Ultrasonic Testing
GB/T 4334 Corrosion of metals and alloys - Test methods for intergranular corrosion of
stainless steels
GB/T 7736 Ultrasonic inspecting method for macro-structure and imperfection of steel
GB/T 10121 Steel products-Method for magnetic particle inspection of tower sample
GB/T 10561-2005 Steel - Determination of Content of Nonmetallic Inclusions -
Micrographic Method Using Standards Diagrams
GB/T 11170 Stainless steel - Determination of multi-element contents - Spark discharge
atomic emission spectrometric method (Routine method)
GB/T 13305 Austenitic stainless steels - Determination of area content of the α-phase -
Micrographic method using STANDARD diagrams
GB/T 15711 Steel Products - Method for Etch Test of Tower Sample
GB/T 17505 Steel and Steel Products - General Technical Delivery Requirements
GB/T 17897 Test of pitting corrosion resistance of stainless steels in the ferric chloride
solution
GB/T 20066 Steel and Iron - Sampling and Preparation of Samples for the Determination
of Chemical Composition
GB/T 20123 Steel and iron - Determination of total carbon and sulfur content Infrared
absorption method after combustion in an induction furnace (routine method)
GB/T 20124 Steel and iron - Determination of nitrogen content - Thermal conductimetric
method after fusion in a current of inert gas
YB/T 5293 Metallic materials - Forging test
3 Ordering Contents
The contract or order for ordering according to this Standard shall include the following
contents:
a) Standard number;
b) Product name;
c) Designation;
d) Dimensions;
e) Weight;
f) The used processing method (see Clause 4);
g) Delivery status;
h) Special requirements.
4 Classification and Code
4.1 Steel bars are divided into the following two categories according to the processing method:
a) Steel for pressure processing UP
1) Hot pressure processing UHP
2) Steel for hot forging UHF
b) Steel for cutting UC
4.2 The processing method of steel bars shall be specified in the contract. If not specified, they
will be supplied as steel for pressure processing.
5 Dimensions, Shape, Weight and Allowable Deviations
5.1 The dimensions, shape and allowable deviations of rolled steel bars shall comply with the
provisions of GB/T 702-2008, and the specific requirements shall be specified in the contract.
If not specified, Group 2 of GB/T 702-2008 shall apply.
5.2 The dimensions, shape and allowable deviations of forged steel bars shall comply with the
provisions of GB/T 908-2008, and the specific requirements shall be specified in the contract.
If not specified, Group 2 of GB/T 908-2008 shall apply.
5.3 The delivery length of steel bars shall usually be 2000mm~12000mm; after negotiation
between the supplier and the purchaser and specified in the contract, it can also be delivered in
fixed length or multiple lengths. The allowable deviation of the length of rolled steel bars is
+50mm
0mm , and the allowable deviation of the length of forged steel bars is +80mm 0mm .
5.4 Steel bars are usually delivered according to actual weight.
6 Technical Requirements
6.1 Designation and chemical composition of steel
6.1.1 The designation and chemical composition (melting analysis) of steel shall comply with
the provisions of Table 1.
6.1.2 The allowable deviation of the chemical composition of the finished steel bar shall comply
with the provisions of GB/T 222.
6.2 Steel smelting method
Steel shall be smelted by refining outside the furnace, or by electroslag remelting or other
smelting methods that meet the requirements of this Standard. When the purchaser specifies a
certain smelting method, it shall be indicated in the contract.
6.3 Delivery status
Steel bars shall be delivered in a heat-treated state. If not specified in the contract, they shall be
delivered in a non-heat-treated state. The recommended heat treatment system for steel bars is
shown in Table A.1. Other heat treatment systems may also be used after consultation between
the supplier and the purchaser, and indicated in the contract.
6.4 Mechanical properties
6.4.1 The heat treatment system for steel bars or specimens shall refer to the provisions of Table
A.1. The size ...