METHOD FOR HELICALLY PIERCING ELECTROSLAG REFINING INGOTS OF LOW-DUCTILE BORON STEEL

FIELD: production of rolled tube, namely ingot piercing processes, particularly for producing tubes of mean and large diameters of electroslag refining ingots of low -ductile steels in tube rolling plants with pilger mills. ^ SUBSTANCE: method for piercing electroslag refining ingots of low ductile steel with boron content 1.3 - 1.8% comprises steps of piercing (deforming) drilled ingots heated up to yielding temperature on mandrel at different revolution number of working rolls. From time moment of biting ingots by means of rolls till time moment of complete mandrel penetration into metal, piercing (deforming) is realized at revolution number of working rolls in range 25 - 30 rev/min. At outlet of mandrel from sleeve revolution number of working rolls is increased till 45 - 50 rev/min and piercing process is realized at elongation degree 1.5 - 1.75. According to invention lowered labor consumption (by two times and more) of conversion of ingot to tube-blank due to elimination of one heating stage, sleeve expanding, tube-blank rolling and cutting them by two parts and lowered (by 8 - 10%) factor of metal consumption due to decreased (by two times) manufacturing waste are provided. ^ EFFECT: reduced cost of conversion and commercial hexahedral tubes of high-cost steels. ^ 2 cl, 1 dwg