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GB/T 33522-2017 (GB/T33522-2017)

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GB/T 33522-2017English145 Add to Cart 0--10 minutes. Auto-delivery. Carburizing bearing steel forgings -- Technical specification GB/T 33522-2017 Valid GB/T 33522-2017


GB/T 33522-2017: PDF in English (GBT 33522-2017)
GB/T 33522-2017
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 77.140.85
J 32
Carburizing Bearing Steel Forgings –
Technical Specifications
ISSUED ON. FEBRUARY 28, 2017
IMPLEMENTED ON. SEPTEMBER 01, 2017
Issued by. General Administration of Quality Supervision, Inspection and
Quarantine;
Standardization Administration of PRC.
Table of Contents
Foreword ... 3
1 Scope ... 4
2 Normative References ... 4
3 Ordering Requirements ... 5
4 Manufacturing Process ... 5
5 Technical Requirements ... 6
6 Inspection Rules and Test Methods ... 9
7 Acceptance and Quality Certificate ... 11
8 Mark and Package ... 11
Appendix A (Informative) Supplementary Technical Requirements ... 13
Carburizing Bearing Steel Forgings –
Technical Specifications
1 Scope
This Standard specifies the ordering requirements, manufacturing process, technical
requirements, inspection rules and test methods, acceptance and quality certificate,
mark and package of carburizing bearing steel forgings.
This Standard is applicable to the ordering, manufacturing and inspection of high-
quality carburizing bearing steel forgings used for manufacturing rolling bearing rings
and rolling elements.
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) are applicable to this document.
GB/T 223 (all parts) Methods for Chemical Analysis of Iron, Steel and Alloy
GB/T 224 Determination of Depth of Decarburization of Steels
GB/T 225 Steel - Hardenability Test by End Quenching (Jominy Test)
GB/T 226 Test Method for Macrostructure and Defect of Steel by Etching
GB/T 231.1 Metallic Materials – Brinell Hardness Test – Part 1. Test Method
GB/T 908 Forged Round and Square Steels Dimension, Shape, Weight and
Tolerance
GB/T 1979 Standard Diagrams for Macrostructure and Defect of Structural Steels
GB/T 6394 Metal – Methods for Estimating the Average Grain Size
GB/T 6402 Steel Forgings – Method for Ultrasonic Examination
GB/T 10561-2005 Steel - Determination of Content of Nonmetallic Inclusions -
Micrographic Method Using Standards Diagrams
GB/T 20066 Steel and Iron-Sampling and Preparation of Samples for the
Determination of Chemical Composition
GB/T 21469 Machining Allowances and Tolerances for Steel Open Die Forgings
on Hammer - General Requirement
GB/T 21470 Machining Allowances and Tolerances for Steel Open Die Forgings
on Hammer - Disks Columns Rings and Seamless Cylindrical Sleeves
GB/T 21471 Machining Allowances and Tolerances for Steel Open Die Forgings
on Hammer - Shafts
JB/T 9179 (all parts) Machining Allowances and Tolerances of Open Die Forgings
on Hydraulic Press
3 Ordering Requirements
3.1 The purchaser shall specify the name, material grade, delivery status and supply
quantity of the forgings in the ordering contract.
3.2 At the time of ordering, the purchaser (or supplier) shall provide the ordering
drawings and related technical documents approved by both sides.
3.3 When the purchaser has supplementary requirements, it shall be specified in the
contract.
3.4 The forgings are delivered in the normalized, tempered and annealed conditions;
or delivered in the state agreed between the supplier and the purchaser.
4 Manufacturing Process
4.1 Smelting
The forgings shall adopt ladle refining or ladle refining and slag re-melting process.
Other smelting methods that guarantee the quality can also be adopted.
4.2 Forging
4.2.1 The forgings shall be forged with steel ingots or rolled (forged) materials. Both
ends of the steel ingot shall be remained enough length for cutting; so as to ensure the
forgings have on shrinkage, looseness and severe compositional segregation.
Forgings shall be forged in a forging equipment with adequate capabilities using
The specimen for smelting analysis shall be sampled during casting period; it shall
have the same furnace number with the steel ingot; the sampling and sample
preparation methods shall be implemented as per the provisions of GB/T 20066. The
electro-slag re-melting smelting analysis shall be based on the smelting analysis when
the consumable electrode is prepared or the sampling method agreed by the supplier
and the purchaser.
6.1.3 Analysis of the finished products
If the purchaser requires sampling and analyzing from the finished forgings, then the
sampling and sample preparation method shall be implemented as per the provisions
of GB/T 20066.
6.2 Hardness test
The hardness test method shall be implemented as per the provisions of GB/T 231.1;
the test positions shall be agreed by the supplier and the purchaser.
6.3 Metallographic examination
6.3.1 Macrostructure inspection and non-metallic inclusion rating
6.3.1.1 The sampling quantities, sampling positions, specimen size for
macrostructure inspection and non-metallic inclusion rating shall be agreed by the
supplier and the purchaser.
6.3.1.2 The macrostructure etching test shall be performed in the 1.1 hydrochloric
acid aqueous solution at 60°C~80°C according to the provisions of GB/T 226; or
perform electrolytic corrosion in 15%~20% (volume ratio) industrial hydrochloric acid
aqueous solution at 30°C; the corrosion voltage is less than 20V; current intensity is
0.1A/cm2~1A/cm2; time is 15min~20min; the corrosions surface is parallel to the
electrode; and the pole spacing is no less than 20mm. Macrostructure inspection shall
be rated as per GB/T 1979.
6.3.1.3 The non-metallic inclusion rating shall adopt Method A to inspect and rate as
per the provisions of GB/T 10561-2005. The specimen size is 20mm×20mm, cut at the
position about 1/2 from the center to the surface of the forgings or forging test block.
6.3.2 Evaluation of grain size
6.3.2.1 The grain size evaluation shall be performed as per the comparison method
in GB/T 6394 or agreed by the supplier and the purchaser.
6.3.2.2 For the forgings that don’t meet the requirements, they can be renormalized,
re-tempered or re-annealed, and then evaluate; the number of reheating treatment
shall not exceed twice.
Appendix A
(Informative)
Supplementary Technical Requirements
A.1 General
Only when specified in the contract, some or all of the following technical requirements
apply. The adoption of technical requirements shall have the same effect as the text of
this Standard. The details of the technical requirements are agreed by both sides; but
the text of this Standard shall not be denied.
A.2 Residual elements
The purchaser can require the supplier to provide the analysis results for the chemical
compositions of titanium, aluminum, oxygen and the like elements; then the sampling
quantity and position shall be agreed by the supplier and the purchaser.
A.3 “SAM” inclusion rating system
A.3.1 In addition to rating of the non-metallic inclusions as specified in 6.3.1.3, the
purchaser can designate to adopt “SAM” inclusion rating system. This is a method to
determine the purity of the bearing steel. In addition to evaluating the serious
conditions, such rating system can also reflect the frequency of the occurrence of
larger particle oxidized inclusions; the results shall be expressed by two rating grades
reflecting the Type-B and Type-D inclusion contents.
A.3.2 The sampling shall be implemented as per the provisions of 6.3.1.1 and 6.3.1.3.
A.3.3 The inclusion rating shall be performed as per 6.3.1.3 or agreed by the supplier
and the purchaser.
A.4 Adding calcium
Without the special permission of the purchaser, the supplier can’t intentionally add
calcium or alloys to deoxidize or control the inclusion morphology. Lime and/or fluorite
are allowed during the slagging period.
A.5 Magnetic powder method
Except for the non-metallic inclusion rating method specified in 6.3.1.3, the purchaser
can designate the magnetic powder method, which shall be agreed by the supplier and
the purchaser.
......
 
(Above excerpt was released on 2018-06-02, modified on 2021-06-07, translated/reviewed by: Wayne Zheng et al.)
Source: https://www.chinesestandard.net/PDF.aspx/GBT33522-2017