Slag Recycled E71T-1 Flux-Cored Wire And Its Cracking Senstivity Analysis

E71T-1 flux cored wire is widely used in shipbuilding, metallurgy, heavy industry, marine platforms and other fields. It is the largest output and most widely used flux cored wire. The operative performances such as weld bead forming, slag detachability, arc stability are mainly base on the natural rutile which is added to the flux. But the worldwide exploration and production of natural rutile present a tigh trend and influence the production and development of E71T-1 flux cored wire. Recent years, with the use of thicker, higher strength steel structure, cold crack in weld joints attract the attention of engineers in the domain of welding.In this paper, the possibility of slag powder instead of natural rutile and the following formula adjustment were studied, and the cold and hot crack susceptibility of E71T-1 type flux-cored wire weld joints and the relationship between deposited metal composition and mechanical properties. The main contents are as follows:1. Partly replace natural rutile by slag powder and adjust formula.Study the physical and chemical properties of recycled slag powder and its impaction on the operative performance of E71T-1 type flux-cored wire. On the basis of a large number of tests result, we research the relationship between weld deposited metal chemical composition and mechanical properties and establishment regression formula of deposited metal chemical composition and mechanical properties which facilitate the adjustment of formula.2. Study the sensitivity of cold crack, and improve the Y groove cold crack test device.The result showed that the segregation of carbon element is the main reason for the riser of the cold crack under the condition of rapid cooling, more martensite will lead high cold crack susceptible.With larger groove angle, thicker test plate and wider gap, the crack sensitive will becomer larger.3. Compared our flux-cored wire with other product at home and abroad in operative perfopmance, mechanical properties and crack susceptible .The results show that the slag detachability, welding spatter rate and welding arc stability of our flux-cored wire are in the middle of the 7 kinds of E71T-1 type flux-cored wire.It also has satisified deposited rate and deposited efficiency.Our flux-cored wire have excellent mechanical perperties and low cold and hot crack susceptible.