二、抗硫化物应力腐蚀开裂SSC试验

Ⅱ. Sulfide Stress Corrosion Cracking Resistance SSCTest

试验按照标准NACE TM 0177-2005进行。按用户要求对试样加载80% AYS（实测屈服强度），试验周期720h。

The test is conducted according to NACE TM0177-2005. According to the user requirements, load the samples at 80% AYS (Actual Yield Strength). The test period is 720h.

2.1 试样

按照ISO 7539-2标准采用四点弯曲试件。

2.1 Sample

According to ISO 7539-2, four-point loaded specimen is adopted in the test.

2.2 试验设备

试样夹具，溶液槽，放大镜

2.2 Test device

Specimen holders, Test tank, Magnifier

2.3温度压力条件

本次试验的试验温度为24±3℃，压力为常压。

2.3 Temperature and pressure

Test pressure is atmospheric pressure and test temperature is 24±3℃.

2.4 试验介质  

本次试验硫化物介质为H2S水溶液。即H2S饱和的5%NaCl+0.5% CH3COOH蒸馏水混合溶液，pH=2.8。通H2S气体之前，用氮气去氧。试验期间溶液pH值不超过4.0。

2.4 Test medium

The test medium is composed of 5.0 wt% sodium chloride and 0.5 wt% glacial acetic acid and saturated H2S aqueous solution (pH=2.8). Aerate nitrogen to remove oxygen before aerating H2S gas. During the test, pH shall not exceed 4.0.

2.5 试验结果  

试验结束后，在低倍显微镜下放大10倍检查试件的受拉伸面。试验结果见表2

2.5 Test results

Examine the presence of crack visually with the aid of a low-power binocular microscope after the test. The results are referred to Table 2.

阀门锻件硫化物应力开裂试验结果

      试样编号                            加载应力(MPa)  浸泡时间   环境开裂裂纹EC    评定

20190622-SXHT-SSC-2-1           256MPa             720h                   无                    通过

20190622-SXHT-SSC-2-2           256MPa             720h                   无                    通过

20190622-SXHT-SSC-2-3           256MPa             720h                   无                    通过