| 简介 |
FIELD : metallurgy.
SUBSTANCE : method comprises manufacture of a sheet semifinished product and thermomechanical processing thereof by multiple heatings and deformations. Thermomechanical processing of sheet semifinished products is carried out in seven stages. The first stage includes an all-around forging on a slab in at least two sets with a total deformation degree of not less than 40±10% at each one, lowering of forging temperature and intermediate heatings in the temperature range from Tih+180 to Tih+490°C. The second stage comprises heating the slab to a temperature (Tih+250÷Tih+420)°C, deformation by hot rolling with a total deformation degree of not less than 80±10% and intermediate heatings. The third stage comprises heating to a temperature (Tih+30÷Tih+70)°C, deformation of the intermediate hot-rolled semifinished rolled products by hot rolling with a total deformation degree of at least 40±10% and intermediate heatings. The fourth stage comprises further deformation of the semifinished rolled products into one or more stages by heating to a temperature (Tih+90÷Tih+130)°C and hot rolling with a total deformation degree from 40 to 70±10% and intermediate heatings. The fifth stage comprises heat treatment of sheet semifinished products at a temperature (Tih+10÷Tih+50)°C for 0.3-1.5 hours in a chamber resistance furnace and subsequent water or air hardening to obtain β-structure. The sixth stage comprises cold rolling of sheets with a total deformation degree from 20 to 60±10%. The seventh stage comprises straightening at a temperature (Tih-20÷Tih-90)°C with subsequent surface treatment.
EFFECT : increasing degree of structure elaboration by increasing the limiting deformation degrees during hot and cold processing with pressure, increasing technological plasticity while maintaining strength and plasticity after hardening heat treatment, decreasing the minimum relative bend radius in the quenched state.
3 cl, 2 tbl |
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