GB/T 5720-2008 in English

《GB/T 5720-2008O形橡胶密封圈试验方法》由TC35（全国橡胶与橡胶制品标准化技术委员会）归口，TC35SC3（全国橡胶与橡胶制品标准化技术委员会密封制品分会）执行，主管部门为中国石油和化学工业联合会。
本标准代替GB/T 5720-1993《Ｏ 形橡胶密封圈试验方法》。本标准规定了实心硫化O形橡胶密封圈的尺寸测量、硬度、拉伸性能、热空气老化、恒定形变压缩永久变形、腐蚀试验、耐液体、密度、收缩率、低温试验和压缩应力松弛的试验方法。本标准适用于实心硫化O形橡胶密封圈。本标准与GB/T 5720-1993的主要差异有：
―――删除附录Ａ《Ｏ 形橡胶密封圈的标准试样》；
―――增加低温性能试验；
―――删除拉伸永久变形的测定；
―――将耐液体试验用Ｏ 形圈片段试样的长度由（９０±２）ｍｍ 改为至少为５０ｍｍ；
―――５．４．１．２条将“限制器的高度为试样截面直径的７５％”改为“试样的硬度在（１０～８０）ＩＲＨＤ 时，限制器的高度为试样截面直径的７５％，试样的硬度在（８１～８９）ＩＲＨＤ 时，限制器的高度为试样截面直径的８５％，试样的硬度在（９０～９５）ＩＲＨＤ 时，限制器的高度为试样截面直径的９０％。”；
―――增加耐腐蚀试样和夹具的图示以及结果判定的图示。

1 Scope

This standard specifies test methods for size measurement , hardness, tensile property, hot air aging, constant deformation compression set, corrosion and liquid resistance, density, shrinkage , low temperature test and compression relaxation of solid vulcanized rubber O-ring.

This standard is applicable to solid vulcanized rubber O-ring (hereinafter referred to as O-ring).

2 Normative References

The following documents contain provisions which, through reference in this standard, constitute provisions of this standard. For dated references, subsequent amendments (excluding corrections) to, or revisions of, any of these publications do not apply. However, the parties who enter into agreement according to this part are encouraged to research whether the latest editions of these documents may be applied. For undated references, the latest edition referred to apply.

GB/T 528-1998 Rubber，Vulcanized or Thermoplastic-Determination of Tensile Stress-Strain Properties (eqv ISO 37:1994)
GB/T 533-1991 Rubber Vulcanized or Thermoplastic-Determination of Density (ISO 2781:2007, IDT)
GB/T 1690-1992 Rubber, Vulcanized-Determination of the Effect of Liquids (neq ISO 1817)
GB/T 2941-2006 Rubber-General Procedures for Preparing and Conditioning Test Pieces for Physical Test Methods (ISO 23529:2004, IDT)
GB/T 3452.2-2007 Fluid Power Systems-O-rings-Part 2: Quality Acceptance Criteria (ISO 3601-3:2005, IDT)
GB/T 3512-2001 Rubber, Vulcanized or Thermoplastic-Accelerated Ageing and Heat Resistance Tests-Air-oven Method(eqv ISO 188:1998)
GB/T 6031-1998 Rubber, Vulcanized or Thermoplastic-Determination of Hardness (Hardness between 10IRHD and 100IRHD) (idt ISO 48:1994)
GB/T 7758-2002 Rubber, vulcanized--Determination of Low-Temperature Characteristics-Temperature-Retraction Procedure (TR Test) (ISO 2927:1997, IDT)
GB/T 7759-1996 Rubber, Vulcanized or Thermoplastic-Determination of Compression Set at Ambient Elevated or Low Temperatures (eqv ISO 815:1991)
GB/T 13643-1992 Rubber, Vulcanized or Thermoplastic-Determination of Compressions Tress Relaxation(Rings) (eqv ISO 6059:1987)
HG/T 2369-1992 Rubber Plastic Tensile Tester Technical Conditions

3 Requirements for Sample and Test Condition

3.1 Requirements for sample

3.1.1 Sample is prepared according to the requirements of GB/T 2941-2006.

3.1.2 Appearance quality of the sample shall meet the requirements of GB/T 3452.2-2007, Grade N.

3.1.3 The samples tested for hardness, tensile property, hot air aging, constant deformation compression set, corrosion test, liquid resistance, density, shrinkage rate, low temperature test and compression stress relaxation are detailed in 5.1.2, 5.2.2, 5.3.2, 5.4.2, 5.5.2, 5.6.2, 5.7.2, 5.8.2, 5.9.2 and GB/T 13643-1992, 4.1.3.

3.2 Test condition

Environmental conditioning of sample and test temperature and time shall be carried out in accordance with GB/T 2941-2006.

Foreword i
1 Scope
2 Normative References
3 Requirements for Sample and Test Condition
4 Measurement of Sample Size
5 Test Procedures
6 Test Report