{"id":13300,"date":"2024-10-28T16:11:10","date_gmt":"2024-10-28T08:11:10","guid":{"rendered":"https:\/\/www.sogaworks.com\/?p=13300"},"modified":"2025-01-10T16:23:17","modified_gmt":"2025-01-10T08:23:17","slug":"weld-passivation","status":"publish","type":"post","link":"https:\/\/www.sogaworks.com\/jp\/blogs\/weld-passivation\/","title":{"rendered":"\u6eb6\u63a5\u4e0d\u52d5\u614b\u5316\uff1a\u30b9\u30c6\u30f3\u30ec\u30b9\u92fc\u6eb6\u63a5\u306b\u304a\u3051\u308b\u8010\u98df\u6027\u306e\u5411\u4e0a"},"content":{"rendered":"

\u30b9\u30c6\u30f3\u30ec\u30b9\u92fc\u90e8\u54c1\u3092\u6eb6\u63a5\u3057\u305f\u5f8c\u3001\u30a8\u30f3\u30b8\u30cb\u30a2 \u306f\u901a\u5e38\u3001\u785d\u9178\u3084\u30d5\u30c3\u5316\u6c34\u7d20\u9178\u3092\u542b\u3080\u9178\u6d17\u30da\u30fc\u30b9\u30c8\u306a \u3069\u3001\u3055\u307e\u3056\u307e\u306a\u5316\u5b66\u85ac\u54c1\u3092\u4f7f\u7528\u3057\u3066\u6eb6\u63a5\u90e8\u3092\u6d17\u6d44\u3059 \u308b\u3002\u3053\u306e\u30d7\u30ed\u30bb\u30b9\u306f\u3001\u4e0d\u52d5\u614b\u5316\u3068\u3057\u3066\u77e5\u3089\u308c \u3066\u3044\u308b\u3002\u3053\u306e\u8a18\u4e8b\u3067\u306f\u3001\u6eb6\u63a5\u306e\u4e0d\u52d5\u614b\u5316\u3068\u306f\u4f55\u304b\u3001\u307e\u305f\u4e0d\u52d5\u614b\u5316\u306e\u4ed5\u7d44\u307f\u306b\u3064\u3044\u3066\u8aac\u660e\u3059\u308b\u3002<\/p>\n\n\n\n

What is Passivation?<\/strong><\/h2>\n\n\n\n

Passivation is a process that uses a strong oxidizing agent to create a dense, protective oxide layer on a metal’s surface. In stainless steel<\/a>, passivation involves using an acidic solution to remove surface iron and other contaminants. This treatment forms a thicker layer of chromium oxide, which greatly improves the stainless steel’s resistance to corrosion.<\/p>\n\n\n\n

\"passivation<\/figure>\n\n\n\n

History of Passivation<\/strong><\/h3>\n\n\n\n

In the 1800s, the chemist Christian Friedrich Sch\u00f6nbein<\/em> discovered the effects of passivation on metals. He immersed iron in concentrated nitric acid and compared it to iron that had not been treated. The treated iron was virtually chemically unreactive compared to the untreated iron.<\/p>\n\n\n\n

As welding and passivation of stainless steel became more popular, the environmental and safety impacts of using nitric acid became more apparent.19 In the early 1900s, a German brewing company found citric acid to be a safer, non-toxic alternative to passivation. In 1990, citric acid had replaced nitric acid in many applications in large quantities. Today, both acids are used in modern passivation processes.<\/p>\n\n\n\n

What Does Weld Passivation Do\uff1f<\/strong><\/h2>\n\n\n\n

Stainless steel is primarily made of iron, chromium, and nickel. Chromium provides its corrosion resistance: when chromium is exposed to oxygen, it forms a thin layer of chromium oxide on the stainless steel\u2019s surface, protecting the iron underneath from rust. During welding, however, localized heating can damage this protective oxide layer, making the weld area more susceptible to contamination. Without passivation, environmental contaminants, like chlorides, can react with exposed iron on the surface and initiate corrosion. Once corrosion begins, it can spread through the weld area and into the entire component.<\/p>\n\n\n\n

\u4e0d\u52d5\u614b\u5316<\/a> helps slow or prevent corrosion in 2 ways. First, It allows iron and iron oxides to dissolve more readily than chromium and its oxides, this process removes the iron-rich layer and increases chromium concentration at the surface. Second, Passivation enhances the oxidation process of chromium to form a thicker inert oxide layer, which protects the underlying metal from environmental contaminants.<\/p>\n\n\n\n

\"advantages<\/figure>\n\n\n\n

After fabrication and welding, passivation is the next critical step for stainless steel parts. Key benefits of weld passivation include:<\/p>\n\n\n\n