晶间腐蚀标准

Standard practices for

Detecting susceptibility to intergranular attack in austenitic stainless steels

奧氏體不銹鋼晶間腐蝕敏感性標準實驗

1.scope

1.應用範圍

these practices cover the following five tests:

1.2 這些實驗包括下列五類：

1.1.1 parctics A- oxalic acid etch test for classification of etch structures of austenitic stainless steels(section 3 to 7, inclusive)

1.1.1實驗A——奧氏體不銹鋼草酸浸蝕試驗後的浸蝕組織分類（包括3－7部分

1.2 the following factors govern the application of these practices:

1.2以下因素主導著這類實驗：

1.2.1 susceptibility to intergranular attack associated with the precipitation of chromium carbides is readily detected in all six tests.

1.2.1晶間腐蝕敏感性同碳鉻化合物的快速析出

1.2.2 sigma phase in wrought chromium-nickel-molybdenum steels. Which may or may not be visible in the microstructure, can

result in high corrosion rates only in nitric acid.

1.2.2在鉻鎳鉬鋼中可見的和不可見的sigma相，只有在硝酸中才會快速腐蝕。

1.2.3 sigma phase in titanium or columbium stabilized alloys and cast molybdenum-bearing stainless alloys, which may or may not be visible in the microstructure, can result in high corrosion rates in both the nitric acid and ferric sulfate-sulfuric acid solutions.

1.2.3在鈦合金或穩定化合金和鑄造鉬柱狀晶中的sigma相，不管在其顯微組織中可見不可見都會在硝酸和硫化鐵溶液中引起嚴重腐蝕。

1.3 the oxalic acid etch test is a rapid method of identifying, by simple etching, those specimens of certain stainless steel grades that are essentially free of susceptibility to intergranular attack associated with chromium carbide precipitates. These specimens will have low corrosion rates in certain corrosion tests and therefore can be eliminated (screened) from testing as ―acceptable.‖

1.3草酸浸蝕試驗是一個快速方法用來使這些本質上晶間腐蝕不敏感的不銹鋼試樣快速析出碳鉻化合物。

1.7 only these stainless steel grades are listed in table one for which data on the application of the oxalic acid etch test

and on their performance in various quantitative evaluation tests are available.

1.7在表一中列出哪些適合用草酸進行浸蝕試驗及各種數量測試下的性能是有效的。

Practice A oxalic acid etch test for classification of etch structures of austenitic stainless steels 2

實驗A——奧氏體不銹鋼草酸浸蝕試驗後的浸蝕組織分類

3.1 the oxalic acid etch test is used for acceptance of material but not for rejection of material. This may be used in connection with other evaluation tests to provide a rapid method for identifying those specimens that are certain to be free of susceptibility to rapid intergranular attack in these other tests. Such specimens have low corrosion rates in the various hot acid tests, requiring from 4 to 20 h of exposure. These specimens are identified by means of their etch structures, which are classified according to the following criteria：

3.1草酸浸蝕法晶間腐蝕試驗一般用來作為材料的評價，不作為材料的判廢標準。这方法一般为其它评价方法提供一个快速途径来鉴定实验试样在各种测试中是否具有晶间腐蚀敏感性。这些在各种热酸试验中腐蚀率都很低的试样，需要承受4至20小时的试验。通过对这些