Hot-rolled stainless steel sheet commonly used method, casting method, and the explosive welding method to produce composite, hot-rolled stainless steel sheet manufacturing method, more common domestic and international applications. Stainless steel sheet of base material is usually a low-carbon steel and the ordinary low-alloy high strength steel, steel sheet from the grassroots to ensure the strength, undone layer materials, the general corrosion resistance of chrome-nickel, typically, double-layer composite plate thickness accounted for 10-20% of the total thickness.
1 welding characteristics
Stainless steel sheet welding, welded together in a single material, the first from the welding sequence, the first primary seam welding, gap welding after welding stratified, and stratified primary weld seam weld junction is the barrier , isolation layer weld stainless steel sheet by welding characteristics of the decision, it can ensure that the composite steel plate welded joints of complex layers of plastic and corrosion resistance of the weld, the weld on carbon steel welded stainless steel, carbon steel there stainless steel weld seam on the issue of dilution due to dilution effect, reducing the chrome-nickel stainless steel weld content in stainless steel weld easily lead to hard and brittle martensite, thereby reducing the ductility and toughness of welded joints Therefore, isolation layer welding gap must select high Cr-Ni duplex and good resistance to dilute Cr-Ni stainless steel electrode. This is the chrome-nickel austenitic stainless steel sheet welding principles in the welding arc welding, the stainless steel at high bluster isolation layer of fill material to do welding, welding parameters properly, the weld can be phase organization in dilution rate of less than 30% of cases, and still not produce a large number of martensite.
2 stainless steel sheet welding of the main problems
â‘´ stratified by carbon, destroy the corrosion resistance of the weld â‘µ primary Cr, Ni alloying elements, resulting in brittle joints â‘¶ transition layer generated by the multi-layer side of the rich ribbon, generated by the primary side of the ribbon off and damaged the anti- corrosion, reduces ductility and toughness.
3 choice of electrode
Stainless steel sheet material in accordance with the conditions of welded joints, a reasonable choice of the grassroots, isolation layer, double layer Types Of Welding Electrode, such as primary carbon steel electrode J422, isolation layer made of stainless steel welding rod A302, A307, A312, stratified selection of A102, A107 , A202 and so on.
4 welding process
Cleaning and preparation before welding â‘´
For multi-layer Ti on both sides of the groove and should be 15-20mm range during the cleaning, detachment of oil and splash, stainless steel groove on both sides are properly protected to prevent welding of the splash and scratch.
â‘µ groove form and size
In order to ensure the stainless steel sheet cladding, primary isolation layer and seam welding quality, effectively control the isolation layer of the weld size, should select the appropriate groove in the form and size, and should ensure precision bevel size.
â‘¶ assembly and tack
Before welding, assembly, first of all to ensure that the assembly clearance, general butt gap of about 2 mm, and strictly control the amount of the wrong side, wrong side of excessive, will directly affect the isolation layer and complex layer of weld quality, the production proved wrong side of stainless steel amount can not exceed 0.5 mm, which is able to control production.
â‘· welding sequence
The same thing to start with the grass-roots backing welding, and welding full each primary seam, and then cleared from the stratified side of the weld root, in order to ensure the slot size, usually with the angle grinder grinding, groove depth 3-4 mm is appropriate , after passing through the X-ray detection and then isolation layer and multi-layer welding seam.
â‘¸ welding standard
Welding isolation layer, reducing the dilution rate, to ensure penetration of the conditions, should be adopted in small current.
â‘¹ process measures
Isolation layer weld seam to be covered with grass roots and more than primary and stratified boundary line 1 mm, the weld switch to maintain a smooth, raised to prevent the weld, or, with the wheel polished, and then stratified seam welding, should be carefully fall clean-up stratified groove Carbon Steel Electrodes surface splash, stainless steel welding needs multiplexed three different electrodes to prevent the misuse of welding rod, to ensure the welding quality.
(A) arc welding machine Current generated by the different types can be divided into DC and AC arc welder arc welding machine into two categories. (1), AC arc welding machine is actually in line with the requirements of step-down transformer, as shown in Figure 16-3. It 220V or 380V supply voltage down to 60-80V (ie welding load voltage), which meets the needs of arc, but also to ensure personal safety. Welding, the arc voltage will drop to normal operation automatically when the operating voltage required for 20-30V, stable arc burning to meet the requirements. Output current is alternating current, according to the needs of Welding Electrode Manufacturers , the current is transferred from the tens of hundreds of amperes amperes. It has a simple structure, convenient, low cost, material saving, easy to use reliable and maintenance advantages, disadvantages arc stability is not as good as DC arc welding machine, for some types of electrodes do not apply. (2), DC arc welding machine can be divided into two categories: direct current arc welding generators and welding rectifiers. DC arc welding generator is composed of AC motors and DC generators, as shown, electric motor driven generator running through to meet the Carbon Steel Electrode requirements issued by the DC. Can be characterized by a stable DC, therefore, easy arc, arc stability and weld quality is good, but the structure is complicated, more difficult to manufacture and maintenance, high cost, use noise. Therefore, it is generally used in the current special requirements of the occasion.