Study of the effect of phosphorus and boron on recrystallization of low-carbon high-strength automobile sheet steel

Abstract

1 With an increase in phosphorus and boron content in low-carbon steels the ferrite grain size increases in hot-rolled semifinished product. 2. Microalloying with boron of low-carbon phosphorus-containing steel promotes cementite particle refinement in the structure of hot-rolled material. 3. An increase in phosphorus content in cold-rolled steel 08YuP leads to acceleration of the recrystallization process particularly in the selective recrystallization stage. 4. Introduction into low-carbon phosphorus-containing steel of microadditions of boron initiates development of the initial stages of primary recrystallization and it promotes earlier completion of it. However, here selective recrystallization slows down. 5. The texture of steel 08YuP microalloyed with phosphorus is characterized by presence of clearly defined crystallographic orientations favorable for forming. Introduction into the steel apart from phosphorus of microadditions of boron sharply reduces the polar density of these orientations. 6. Steel 08YuP has higher strength properties and texture forming indices RG and H than steel 08Yu of higher drawing category with similar values of normal plastic anisotropy coefficient\(\bar R\). This makes it possible to recommend steel 08YuP for forming a broad range of automobile articles. The level of the indices in question for steel 08YuPR is lower than for steels 08Yu and 08YuP.