50W耐候鋼焊接鋼管的焊接工藝探討

Discussion on Welding Process for 50W Weather-resistant Steel Pipe

摘要: 介紹不同合金元素、焊縫組織類型和晶粒尺寸對低合金鋼耐蝕性的影響，并在此基礎上設計選擇了50W耐候鋼的焊材、焊接坡口和焊接能量參數(shù)；分析了50W耐候鋼焊接接頭的顯微組織、力學性能、耐蝕性能等。分析認為：50W耐候鋼焊縫金屬組織為細密的針狀鐵素體時，焊接接頭的耐蝕性最優(yōu)；通過控制冷卻速度和焊接熱輸入，可使焊縫得到充沛的針狀鐵素體組織，獲得符合耐蝕性要求的50W耐候鋼焊接接頭。

Abstract: Elaborated in the article are the influences on the corrosion resistance of the low alloy steel by such factors as different alloy elements, weld microstructure type and grain size.Accordingly, the welding consumable, welding bevel and welding energetic parameters for the 50W weather-resistant steel are determined.Analyzed are the main aspects of the 50W steel, including welded joint microstructure, mechanical properties and corrosion resistance, etc.It is regarded via the analysis that when the weld metal of the 50W weather-resistant steel has a fine acicular ferrite structure, the welded joint demonstrates the best corrosion resistance.Accordingly, properly controlling cooling rate and welding heat input will make the weld have sufficient acicular ferrite structure, and thus get the 50W weather-resistant steel welded joint meeting relevant requirement for corrosion resistance.