There is an approximate relationship between the force required to deflect a pure elastomer a given amount, and the hardness of the elastomer. In general, the harder the elastomer, the greater the force required. In the case of XXXX ’ metal particle-filled elastomers, this relationship is much less definite, and in some instances, these materials demonstrate deflection/ hardness and deflection/thickness behavior contrary to that which would be anticipated for conventional elastomer compounds.
纯净弹性体达到给定变形量所需的力以及弹性体的硬度之间有一个近似关系，通常，弹性体的硬度越大，则需要的力就越大。对于XXXX 金属颗粒填充弹性体，该关系则很不明确，在有些情况下，这些材料的变形量/硬度和变形量/厚度特性与那些传统弹性体混合物的预期特性相反。
The inclusion of metal particles in the elastomer results in a mechanically structured material. This mechanical structure has a marked effect on the deflection of the elastomer under compressive loads, and in some instances, harder materials deflect more than softer materials.
该弹性体内含有金属颗粒，则导致其成为一种机械结构材料。该机械结构对弹性体在压缩载荷下的变形量有显著影响，在有些情况下，较硬材料会比较软材料的变形量更大。
Compressive load-deflection data for many popular conductive elastomer materials and shapes are given in Figures 1-6. (For “line contact” gaskets, it is more convenient to express the load in terms of pounds per linear inch instead of pounds per square inch).
图1-6给出了许多常用导电弹性体材料和型材的压缩载荷－变形量数据。（对于“线接触”垫片，采用磅每线性英寸为单位来表示载荷要比磅每线性平方英寸更为方便）。
For compression-deflection data on other XXXX gaskets, contact our Applications Engineering Department.
对于其他XXXX 垫片的压缩－变形量数据，请与我们的应用工程部联系。
Stress Relaxation
应力松弛
As important as Compression Set and Compression-Deflection, is the Stress Relaxation characteristic of a gasket.
垫片的应力松弛特性与压缩永久变形和压缩－变形量同等重要。
If an elastomer gasket is subject to a compressive load, it will deflect. There is a stress/strain relationship, which for an elastomer is generally non-linear except for very small deflections. After the load is applied, a stress decay occurs within the polymer resulting from the internal rearrangement of the molecular structure. An approximate rule is that the relaxed stress for cured silicone will finally settle at 70 to 75 percent of the initial stress.
如果弹性体垫片受到一个压缩载荷，它将会发生变形。存在有一个应力/应变的关系，针对弹性体它通常是非线性的，除非变形量非常小。在施加了载荷之后，由于分子结构的内部重排作用，聚合体内将会发生应力松弛。其近似规则为：硫化硅树脂的松弛应力最终将稳定为初始应力的70%到75%。
There are two ways in which an elastomer gasket can be loaded to a desired value. One way is to load it to a point, let it relax, and reapply the load to restore the original stress. The next time it will relax, but not as much. If this is repeated a sufficient number of times, the correct static load on the gasket will reach equilibrium.
要将弹性体加载到理想数值，有两种方法。一种方法是先将其加载到一个载荷点，使其松弛，并再次施加载荷以恢复初始应力。它将再次松弛，但不会有那么多。如果这些重复足够次数，垫片上的正确静载荷将达到平衡。
A more practical way to reach the design value of stress is to load the gasket to 125 percent of its final design value, so that after the relaxation process is completed the gasket will settle to 100 percent of the design load. This is very reproducible.
达到设计应力值的更为实用的方法是向垫片加载其最终设计值的125%，这样在松弛过程完成之后，垫片将稳定在设计载荷的100%。这是可复制的。
华译网上海翻译公司曾经翻译过大量有关应力松弛的资料文件，Beijing Chinese Subtitling Translation Service Agency has translated many technical documents about Stress Relaxation.Figure 7 shows a typical stress relaxation curve for XXXX ’ conductive elastomers.
图7显示的是XXXX 导电弹性体的典型应力松弛曲线。
LOACING
加载
stress relaxation
应力松弛
Less than one hour
小于一个小时
Approximately 75% of linear initial stress
线性初始应力的约75%
Stress (%)
应力 (%)
Figure 7. Stress Relaxation
图7：应力松弛
Compression Set
压缩永久变形
When any elastomer is deformed for a period of time, some of the deformation is retained permanently even after the load is removed. The amount of permanent deformation, as measured by ASTM D395, is termed “Compression Set.” Compression set is measured under conditions of constant deflection (ASTM D395 Method B) and is normally expressed as a percentage of the initial deflection, not as a percentage of the initial height.
当弹性体变形持续一段时间之后，有些变形即使在移除载荷之后仍永久保持。由ASTM D395所测量得到的永久变形量，被称为“压缩永久变形”。压缩永久变形是在恒定变形量条件下测量得到的（ASTM D395中的方法B），通常表示为初始变形量的百分比，而不是初始高度的百分比。
For gaskets that are used once, or where the gasket/flange periphery relationship is constant (such as a door gasket), compression set is of minor significance if the original load condition and the service temperature are within the design limitations of the gasket material.
对于那些只使用一次的垫片，或者垫片/法兰外围关系恒定（例如门的垫片），如果初始载荷条件和工作温度处于垫片材料的设计限永久变形制之内，则压缩永久变形的重要性较小。
For gaskets that are randomly reseated one or more times in normal service life, it is important that the maximum change in gasket thickness does not exceed twice the maximum mismatch between the opposing mating surfaces.
对于那些在正常寿命内随意重新装设一次或多次的垫片，垫片厚度的最大变化量不能超过相对配合表面之间最大失配量的两倍，这是很重要的。
Hi = Initial height
Hi = 初始高度
Hd = Deflected height (Normally 75% of Hi)
Hd = 变形后高度（通常为Hi的75%）
Hf = Final height (After load is removed)
Hf = 最终高度（移除载荷之后）
Compression Set = (Hi-Hf)/ (Hi-Hd)×100%
压缩永久变形＝(Hi-Hf)/ (Hi-Hd)×100%
Figure 8. Formula for Calculation of Compression Set
图8：压缩永久变形的计算公式 |
