Stainless steel electrode can be divided into chromium stainless steel welding rod and chrome-nickel stainless steel electrode, who meet the national standard, according the provisions of GB GB/T983-1995 assessment of these two types of electrodes.
Chromium stainless Nickel Electrodeschromium stainless steel corrosion (oxidizing acids, organic acids, cavitation) heat resistance and corrosion resistance. Usually selected as power plants, chemical, petroleum and other equipment and materials. The general case of chromium stainless steel weldability poor, should pay attention to the welding process, heat treatment conditions and the appropriate choice of welding electrodes.
1, martensitic stainless steel welding:
The martensitic stainless steel including chromium containing 5 to 9% in the chromium steel containing 12% Cr, high-chrome steel. Such steel hardened tendency, after welding, is easy to produce a high hardness martensite and bainite so that brittleness increases, the residual stress is also large, easy to produce cold cracks. Must be so general before welding preheat and inter-layer insulation, high-temperature tempering after welding yet cooled.
2, 13 chrome stainless steel welding:
Such the chromium steel welding after sclerosing easily cracks, using welding of the similar chromium stainless steel electrode (A202, A207), you must preheat and post-weld above 300 ℃ and 700 ℃ tempering slow cooling. If the weldments can not weld treatment, the application of chromium stainless steel electrode welding (A107, A207).
3, 17 chrome stainless steel welding:
Such chromium steels are generally for improving the corrosion resistance and weldability, plus the amount of the stabilizing elements titanium, niobium, molybdenum, weldability than chromium 13 steel as well, and can be the same type of chromium stainless steel electrode (A302, A307) welding. Before welding, weldment should be about 200 ℃ preheat about 800 ℃ tempering after welding. Can also be used chrome-nickel stainless steel electrode (A107, A207), post-weld heat treatment.
Chrome-nickel stainless steel electrode for use
Chrome-nickel stainless steel electrode with good corrosion and oxidation resistance, it is widely used in the manufacture of chemicals, fertilizers, petroleum, food, medical devices and equipment. In recent years, with China's industrial development, the chrome-nickel stainless steel electrode varieties there are more than thirty kinds, basically meet the construction needs of our country.
Chrome-nickel stainless steel welding by repeated heating, easy precipitation charcoals, thereby reducing the corrosion resistance and mechanical properties, therefore, the chrome-nickel stainless steel welding equipment operating conditions (temperature and medium types, etc.) should be based on properly select the welding rod, and when used to note the following:
1, stainless steel electrode coating usually titanium calcium type and two low-hydrogen. Titanium calcium typeStainless Steel Welding Electrodesgenerally shallow arc wear degrees, suitable for sheet overlooking welding (manual welding), are not suitable for all-position welding. Stainless steel core resistance the AC welding DC welding easy red, so, as far as possible, using DC welding. The low hydrogen type stainless steel electrode suitable for the above board in all position welding.
2, all kinds of stainless steel welding rod should be used to keep dry, titanium calcium type coating should bake 1 hour at 150 ~ 250 ℃, the low hydrogen drugs skin shall be subject to 200 ~ 300 ℃ bake 1 hour (not repeated drying or drug skin easy to crack and fall off), to prevent the electrode coating glue oil and other dirt, so as not to the the weld increase the amount of carbon and affect the quality of welding.
To prevent heating intergranular corrosion, welding current is not too large, generally about 20% lower than the carbon steel electrode, at the same time the arc is not too long, rapid cooling layer to the narrow channel welding appropriate.
4, the weld ferritic amount, according to the chemical composition from She Feier and flute Lung Find.