GB/T 38885-2020 PDF English
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General specification for ultra-high cleanliness of high carbon chromium bearing steel
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GB/T 38885-2020: PDF in English (GBT 38885-2020) GB/T 38885-2020
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 77.140.10
H 40
General specification for ultra-high cleanliness of high
carbon chromium bearing steel
ISSUED ON: JUNE 02, 2020
IMPLEMENTED ON: DECEMBER 01, 2020
Issued by: State Administration for Market Regulation;
Standardization Administration of PRC.
Table of Contents
Foreword ... 3
1 Scope ... 4
2 Normative references ... 4
3 Order content ... 7
4 Dimensions, appearance, weight ... 7
5 Technical requirements ... 9
6 Test method ... 15
7 Inspection rules ... 17
8 Packaging, marking and quality certificate ... 20
General specification for ultra-high cleanliness of high
carbon chromium bearing steel
1 Scope
This standard specifies the order content, size, shape, weight, technical
requirements, test methods, inspection rules, packaging, markings and quality
certificates of ultra-high cleanliness of high-carbon chromium bearing steel.
This standard is applicable to the hot-rolled or forged round steel, wire rod, cold-
drawn round steel and steel wire which has a diameter of not more than 150
mm for the production of bearing rings and rolling elements with long contact
fatigue life performance of automobiles, railways, energy sources, CNC
machine tools(hereinafter referred to as steel).
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 standard.
GB/T 223.5 Steel and iron - Determination of acid-soluble silicon and total
silicon content - Reduced molybdosilicate spectrophotometric method
GB/T 223.9 Iron steel and alloy - Determination of aluminum content -
Chrome azurol S photometric method
GB/T 223.11 Iron, steel and alloy - Determination of chromium content -
Visual titration or potentiometric titration method
GB/T 223.23 Iron, steel and alloy - Determination of nickel content - The
dimethylglyoxime spectrophotometric method
GB/T 223.26 Iron, steel and alloy - Determination of molybdenum content -
The thiocyanate spectrophotometric method
GB/T 223.29 Iron steel and alloy - Determination of lead content - Carrier
precipitation-xylenol orange spectrophotometric method
GB/T 223.31 Iron steel and alloy - Determination of arsenic content -
round, square and hexagonal steels
GB/T 908-2019 Forged bars for dimensions, shape, weight and tolerances
GB/T 2101 General requirement of acceptance packaging marking and
certification for section steel
GB/T 2103 General requirements for acceptance, packing, marking and
quality certification of steel wire
GB/T 4162-2008 Forged and rolled steel bars - Method for ultrasonic testing
GB/T 4336 Carbon and low-alloy steel - Determination of multi-element
contents - Spark discharge atomic emission spectrometric method (routine
method)
GB/T 6394 Metal - Methods for estimating the average grain size
GB/T 10561-2005 Steel - Determination of content of nonmetallic inclusions
- Micrographic method using standards diagrams
GB/T 11261 Steel and iron - Determination of oxygen content - The pulse
heating inert gas fusion-infra-red absorption method
GB/T 14981-2009 Dimension shape mass and tolerance for hot-rolled round
wire rod
GB/T 18254-2016 High-carbon chromium bearing steel
GB/T 18579 High-carbon chromium bearing steel wires
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 20125 Low-alloy steel - Determination of multi-element contents -
Inductively coupled plasma atomic emission spectrometric method
GB/T 32548 Determination of iron, tin, antimony, cerium, lead and bismuth -
Inductively coupled plasma - mass spectrometric method
GB/T 38683-2020 Method of ultrasonic testing for large inclusions in bearing
steel
JB/T 10510 Test method for contact fatigue of rolling bearing material
5.14.4 The surface of the stripped, polished, machine-polished steel shall not
have defects.
5.15 Contact fatigue life
The rated life L10 of the steel under the maximum contact stress of 4500 GPa
shall not be less than 1 × 107 times.
6 Test method
6.1 Dimensions and appearance
Steel size measurement is carried out by a caliper or template that can ensure
the necessary accuracy.
6.2 Chemical composition
6.2.1 The analysis method of chemical composition shall be carried out
according to the general methods such as GB/T 4336, GB/T 20123, GB/T
20125, GB/T 32548. For arbitration, it shall be according to the provisions of
GB/T 223.5, GB/T 223.9, GB/T 223.11, GB/T 223.23, GB/T 223.26, GB/T
223.29, GB/T 223.31, GB/T 223.47. GB/T 223.50, GB/T 223.53, GB/T 223.62,
GB/T 223.63, GB/T 223.77, GB/T 223.85, GB/T 223.86.
6.2.2 The oxygen content specimen shall be tested after fully removing the
decarburized layer. Its analysis method shall be carried out according to GB/T
11261.
6.2.3 The analysis method of titanium content shall be determined by the
supplier and the buyer through negotiation.
6.3 Mechanical properties
The test method of Brinell hardness is in accordance with the provisions of GB/T
231.1. The tensile test method is in accordance with GB/T 228.1.
6.4 Macroscopic
The macroscopic acid leaching test method is carried out according to GB/T
226. The rating diagram is carried out according to Appendix A in GB/T 18254-
2016.
6.5 Macroscopic inclusions
Macroscopic inclusions shall be carried out according to the requirements of
GB/T 38683-2020.
6.6 Microscopic inclusions
Specimens of non-metallic inclusions are quenched and tempered in
accordance with 6.15 and observed at a magnification of 100 times. The
evaluation method and rating diagram are performed in accordance with the
method A in GB/T 10561-2005.
6.7 Decarburization layer
The measurement of the depth of the total decarburization layer is carried out
in accordance with the metallographic method in GB/T 224-2019.
6.8 Microstructure
For microstructure testing, a transverse sample is taken. The polished surface
is etched with a 2% nitric acid alcohol solution and observed at a magnification
of 1000 times. It is rated according to the level 5 rating diagram in Appendix A
of GB/T 18254-2016.
6.9 Carbide inhomogeneity
6.9.1 For the testing of carbide network, take transverse specimens; quench
and temper it according to 6.15; use 4% nitric acid alcohol solution to etch it
after polishing. The spheroidizing annealing steel is rated according to the level
6 rating diagram in Appendix A of GB/T 18254-2016 at a magnification of 500
times. The supplier can also evaluate the carbide network on the longitudinal
specimen, but the transverse direction shall prevail.
6.9.2 For the testing of carbide strip, take longitudinal specimens. Quench and
temper it according to 6.15 in the annealed state; use the 4% nitric acid alcohol
solution to etch it after polishing. Make evaluation at the magnification of 100
times and 500 times. Follow the level 8 rating diagram in Appendix A of GB/T
18254-2016 to evaluate the degree, size and shape of carbide aggregation.
6.9.3 For the testing of carbide liquid precipitation, take the longitudinal
specimen. Follow the requirements of 6.15 to perform quenching and tempering.
After polishing, use the 4% nitric acid alcohol solution to etch it. Evaluate it
according to the level 9 rating diagram in Appendix A of GB/T 18254-2016 at
the magnification of 100 times.
6.10 Microscopic porosity
For the testing, take the longitudinal specimen for quenching and tempering
according to 6.15. Evaluate it according to the level 10 rating diagram in
Appendix A of GB/T 18254-2016 at the magnification of 100 times.
6.11 Grain size
right to conduct inspection and acceptance in accordance with the provisions
of this standard.
7.2 Inspection classification
7.2.1 Type inspection
7.2.1.1 In one of the following situations, the manufacturer shall conduct type
inspection:
a) Trial type identification of new product or the trans-plant production of old
products;
b) After normal production, if there are major changes in materials, processes,
and equipment that may affect product performance;
c) When the production is restored after suspension for more than 1 year;
d) When there is a big difference between the exit-factory inspection result
and the last type inspection result;
e) During normal production, inspection shall be carried out every 1 year;
f) When the contract requires type inspection.
7.2.1.2 See Table 14 for type inspection items, sampling quantity and sampling
locations.
7.2.1.3 When one of the inspection items is unqualified, the type inspection fails.
7.2.2 Exit-factory inspection
7.2.2.1 Group-batching rules
The steel shall be inspected and accepted by batch. Each batch shall be
composed of steel with the same heat number, the same designation, the same
size, the same delivery status, the same heat treatment furnace batch.
7.2.2.2 Sampling quantity and sampling location
7.2.2.2.1 See Table 14 for the sampling quantity and sampling location of each
batch of steel.
......
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.
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