CAJ | 학술논문

1Cr18Ni9Ti不锈钢球头在焊接后经酸洗，表面存在粗糙的腐蚀凹坑。通过采用S-3700N扫描电子显微镜、能谱分析仪、金相显微镜等对表面粗糙的腐蚀凹坑进行成因分析。结果表明：球头在焊接过程中产生了局部敏化现象，球头的晶粒组织细于与之配合的外套螺母组织，使得球头的耐腐蚀性低于外套螺母，在酸洗去氧化皮的过程中，外套螺母与球头的焊缝区、接管嘴的焊缝区之间形成缝隙，酸洗液中的正负离子移动受到了阻滞，导致缝隙处发生严重腐蚀，最终表现为球头表面的点状腐蚀形貌。定期更换酸洗槽液，降低Cl-浓度，以及在酸洗过程中活动零件，可以减少该类腐蚀的产生。
1Cr18Ni9Ti불수강구두재한접후경산세，표면존재조조적부식요갱。통과채용S-3700N소묘전자현미경、능보분석의、금상현미경등대표면조조적부식요갱진행성인분석。결과표명：구두재한접과정중산생료국부민화현상，구두적정립조직세우여지배합적외투라모조직，사득구두적내부식성저우외투라모，재산세거양화피적과정중，외투라모여구두적한봉구、접관취적한봉구지간형성봉극，산세액중적정부리자이동수도료조체，도치봉극처발생엄중부식，최종표현위구두표면적점상부식형모。정기경환산세조액，강저Cl-농도，이급재산세과정중활동령건，가이감소해류부식적산생。
Corrosion pits were found at the surface of a 1Cr18Ni9Ti stainless globe after acid pickling. The causes for the corrosion pits were analyzed by using scanning electron microscopy ( SEM ) , energy dispersive spectrum ( EDS ) , and metallographic microscopy. The results show that the globe became locally sensitized in the welding process. The grain size of the globe was smaller than that of the out nut, and consequently, the corrosion resistance of the globe was weaker than that of the out nut. In the acid pickling process, the gaps formed between the out nut and the globe weld zone as well as between the out nut and the mouth weld zone. The moving of positive and negative ions in the pickling solution was blocked, causing serious corrosion in the gaps. As a result, pitting corrosion was present at the surface of the globe. Periodic replacement of the pickling bath, reducing Cl ion concentration, and moving parts in the pickling process can reduce the generation of such corrosion.