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This standard is developed in accordance with the rules given in GB/T 1.1-2009.
This standard replaces GB/T 246-2007 Metallic materials-Tube-Flattening test in whole. The following technical changes have been made with respect to GB/T 246-2007:
--The title is modified as "Metallic materials-Tube-Flattening test";
--"Scope" is modified (see chapter 1);
--Headings are added for Table 1 and Figure 1 respectively Table title and figure caption is added in Table 1 and Figure 1 respectively; the note of pipe wall thickness symbol in table 1 is modified (see Table 1 and Figure 1);
--"Test principle" is modified (see Chapter 3);
--Editorial changes are modified for "test procedure" (see Chapter 6);
--"Daylight opening" of Chapter 7 d) in original standard is modified as "the distance (H) between two platens under the force".
This standard is identical with ISO 8492:2013 Metallic materials-Tube-Flattening Test.
The following editorial changes have been made in this standard:
--Table title and figure caption is added in Table 1 and Figure 1 respectively.
This standard was proposed by China Iron and Steel Industry Association.
This standard is under jurisdiction of SAC/TC 183 National Technical Committee on Iron and Steel of Standardization Administration of China.
The previous editions of the standard replaced by this standard are as follows:
This standard specifies methods of flattening test for the determination of plastic deformation of metallic conduit with circular cross-section, which can be used to reveal the defects.
In addition to the relevant product standards, this standard is applicable to metallic conduits with outer diameter no more than 600mm and wall thickness no more than 15% of the outer diameter.
2 Symbols, terms and units
See Table 1 and Figure 1 for the symbols, terms and units adopted in this standard.
Table 1 Symbols, Terms and Units
Symbol Term Unit
aa Wall thickness mm
b Inner width of sample after flattening mm
D Outer diameter of metallic conduit mm
H Distance between two platens under the force mm
L Sample length mm
a This parameter is also represented by other symbols in the steel pipe standard.
3 Principle
Flatten the sample of metal pipe end or sample with specified length, cut from a tube in a direction perpendicular to the longitudinal axis [See Figure 1 a) and Figure 1 b) ] , until the value of distance between platens under the action of flattening force meet the requirements of the relevant product standards.
If it's closed flattening, the width of inner surface contact area shall be at least half of the inner width b after normal flattening [see Figure 1 c)].
(b) (c)
Figure 1 Schematic Diagram for the Flattening Test
4 Apparatuses
The test machine shall be able to flatten the sample to the specified distance H between the two parallel platens which shall be of sufficient rigidity.
The width of the platen shall be greater than that of the flattened sample, i.e., at least 1.6D. And the length of the platen shall be not less than the sample length.
Foreword i Introduction ii 1 Scope 2 Symbols, terms and units 3 Principle 4 Apparatuses 5 Sample 6 Procedures 7 Report
ICS 77.040.10 H 23 GB 中华人民共和国国家标准 GB/T 246—2017/ISO 8492:2013 代替GB/T 246—2007 金属材料 管 压扁试验方法 Metallic materials—Tube—Flattening test (ISO 8492:2013, IDT) 2017-07-12发布 2018-04-01实施 中华人民共和国国家质量监督检验检疫总局 发布 中国国家标准化管理委员会
金属材料 管 压扁试验方法 1范围 本标准规定了测定圆形横截面金属管塑性变形能力的压扁试验方法，也可用来揭示其缺陷。 除相关产品标准规定以外，本标准适用于外径不超过600 mm且壁厚不超过外径15%的金属管。 2符号、名称和单位 本标准使用的符号、名称和单位见表1和图1。 表1符号、名称和单位 符 号 名 称 单 位 aa 管壁厚度 mm b 压扁后试样的内宽度 mm D 金属管外径 mm H 力作用下两压板之间的距离 mm L 试样长度 mm a在钢管标准中也用其他符号表示此参数。
