30HX903.pdf_第1页
30HX903.pdf_第2页
全文预览已结束

下载本文档

版权说明:本文档由用户提供并上传,收益归属内容提供方,若内容存在侵权,请进行举报或认领

文档简介

mg rover group engineering standards issue no:mgr es: title: page 1 of 2 date: - printed copy is uncontrolled - check issue is current - 3 hardness of elastomeric materials august 1991 30.hx.903 1scope these methods are applicable to all elastomeric materials, giving a direct reading or apparent hardness value. methods a and c measure hardness in the range 30 - 90 irhd. method b measures hardness in the range 10 - 90 irhd. method d measures hardness above 20 shore d. standard hardness values can only be obtained by using test pieces of standard dimensions as hardness value is dependent on the dimensions of the test pieces, the thickness usually being the most critical dimension. bs.903: part a26 and astm d2240 have been used as a basis. 2apparatus 2.1method a - durometer hardness tester irhd to bs 903 part a57. 2.2method b - suitable deadweight hardness tester, to bs 903. 2.3method c - micro-hardness tester, to bs 903. 2.4method d - durometer hardness tester shore d to astm d2240. 3.specimen preparation (applicable if moulded sheet material is not available). if fabric is attached to or embedded in the samples it shall be removed before cutting test pieces. the method of removal shall be mechanical. surface irregularities shall be removed by means of buffing. tests intended to be comparable shall be made on test pieces of similar thickness, where the sample thickness is below that specified for the procedure, but not less than 2 mm thick, a maximum of two test pieces may be superimposed to obtain the test thickness; the disparity of thickness between any two pieces shall not exceed t2/30. (where t is the mean thickness in mm). 4test selection 4.1it is recommended that measurement is mane with methods a, b or c as applicable. measurements are made using method d only when values greater than 90 irhd are obtained using methods a, b or c. 5procedure 5.1method a - applicable to materials of thickness greater than 4mm. 5.1.1calibrate the hardness tester using standard test blocks. 5.1.2 support the specimen on a horizontal rigid surface and apply the durometer. mg rover group engineering standards issue no:mgr es: title: page 2 of 2 date: - printed copy is uncontrolled - check issue is current - 3 hardness of elastomeric materials august 1991 30.hx.903 5.1.3read off the hardness value given in irhd (international rubber hardness degrees) immediately after the foot is in contact with the specimen. 5.1.4carry out the test at five points distributed over the test specimen on each of three test pieces. 5.2method b - applicable to materials of thickness greater than 4 mm. 5.2.1switch on the apparatus vibrator. 5.2.2lower the foot so that it presses on the test piece with the requisite force. 5.2.3immediately afterwards lower the indentor to apply the pre-load and maintain this force for five seconds. 5.2.4after this period apply the major load and maintain for 30 seconds. 5.2.5read off the hardness value in irhd. 5.2.6carry out the test at five points distributed over the test specimen on each of three test pieces. 5.3method c - applicable to materials of thickness less than 4 mm but greater than 1 mm. 5.3.1switch on the apparatus. 5.3.2adjust the platform so that it presses on the test piece with the requisite force. 5.3.3immediately afterwards lower the indentor to apply the pre-load and maintain this force for five seconds. 5.3.4after this period apply the major load and maintain for 30 seconds. 5.3.5read off the hardness value in irhd. 5.3.6carry out the test at five points distributed over the test specimen on each of three test pieces. 5.4method d - applicable to materials of thickness greater than 4mm. 5.4.1check calibration of hardness tester using a calibration block. 5.4.2support the specimen on a horizontal rigid surface and apply the durometer. 5.4.3read the hardness value given

温馨提示

  • 1. 本站所有资源如无特殊说明,都需要本地电脑安装OFFICE2007和PDF阅读器。图纸软件为CAD,CAXA,PROE,UG,SolidWorks等.压缩文件请下载最新的WinRAR软件解压。
  • 2. 本站的文档不包含任何第三方提供的附件图纸等,如果需要附件,请联系上传者。文件的所有权益归上传用户所有。
  • 3. 本站RAR压缩包中若带图纸,网页内容里面会有图纸预览,若没有图纸预览就没有图纸。
  • 4. 未经权益所有人同意不得将文件中的内容挪作商业或盈利用途。
  • 5. 人人文库网仅提供信息存储空间,仅对用户上传内容的表现方式做保护处理,对用户上传分享的文档内容本身不做任何修改或编辑,并不能对任何下载内容负责。
  • 6. 下载文件中如有侵权或不适当内容,请与我们联系,我们立即纠正。
  • 7. 本站不保证下载资源的准确性、安全性和完整性, 同时也不承担用户因使用这些下载资源对自己和他人造成任何形式的伤害或损失。

评论

0/150

提交评论