The oxygen content at end point of ultra-low carbon steel is directly related to the subsequent fabrication processing and quality of final product. The bottom blowing in the process of converter smelting and the calculating parameters of sublance model system are optimized by company so that the intensity of bottom blowing gas supply is increased, stir of bottom blowing to molten pool is strengthened and bottom blowing gas supply mode is established for ultra-low carbon steel. The results showed that the oxygen content at end point could be reduced, hit ratio of carbon content as well as temperature and oxygen content for ultra-low carbon steel at end point could be improved with the above process, which could provide better molten steel for the subsequent processes.

In the process of converter steelmaking, the carbon in hot metal and oxygen blown in form the gas mixture of CO and a small amount of CO₂ under the condition of high temperature as well as it becomes the converter flue gas. The change trend of concentration curve for CO in flue gas provides the operator with dynamic state of slag. The slag could be effectively prevented to be thick and splashed by referring to the curve of concentration of CO in flue gas at end point of converter steelmaking and concentration of CO in flue gas in the process as well as adjusting the position of oxygen lance and opportunity of adding slag charge so that the end point control is accurate and smelting is stable and trouble-free.

In this paper, it is mainly studied the comparison of feasibility, technology method and metallurgical effects for calcium treatment of high calcium line under the existing production conditions of converter steel-making with those of original iron calcium line so as to further optimize treatment process of high calcium line, improve recovery rate of calcium and fluidity of molten steel as well as reduce cost of calcium treatment per ton of steel and dust emissions.

In this paper, the comparative experiment of non-oriented silicon steel samples with weights of 1 kg (28 pieces) and 0.5 kg (16 pieces) is mainly introduced. It was found that the accuracy of the two methods was consistent, the samples with weight of 0.5 kg were more effective in quality control, time and materials consumption were saved as well as labour intensity could be reduced through comparing the data.

In this paper, it is introduced the process of technical study on manufacturing paper-thin steel strip of grain oriented silicon steel with thickness of 0.08 mm for medium frequency equipment by taking the common grain oriented silicon steel (CGO) with thickness of 0.27 mm produced by our plant as raw material as well as studied the effects of heat treatment technology with different annealing temperatures and running speeds of unit (i.e. holding time) on magnetic property of grain oriented silicon steel. 900 ℃ × 10 m/min is determined to be the optimum heat treatment technology as well as the manufacturing process of paper-thin steel strip of grain oriented silicon steel with good medium and high frequency electromagnetic property that magnetic induction intensity B₈ = 1.846 T, iron loss P_1.5/400 = 11.15 W/kg and coercive force H_c = 53.57 A/m is obtained.

The hot rolled coil plate with thickness of 3~6 mm for high strength welded pipe is successfully developed with the composition design of low carbon and microalloying of niobium and titanium as well as controlled rolling and controlled cooling process with 2 250 mm hot rolling production line of Baotou Steel. Its yield strength is greater than 670 MPa, tensile strength is greater than 750 MPa and percentage elongation after fracture is greater than 19% so that the matching of strength and toughness is good as well as it is with good cold bending and welding performances, which could satisfy the manufacture of high strength welded pipe for customers. As a result, the batch production and supply of thin gauge hot rolled coil plate product for high strength welded pipe of Baotou Steel are realized.

In order to meet the development needs of light weight, high strength, energy-saving and cost-reducing in automotive industry, the hot-dip galvanized 380 MPa grade low alloy high strength steel HC380LAD + Z for automobiles is successfully developed by Baotou Steel through the composition design of microalloying of Nb and Ti combining with reasonable hot rolling and controlled rolling as well as pickling and galvanizing technologies based on advanced equipment and technological characteristics. The production results and using effect of users showed that all its properties could meet the requirements of EN 10346-2015 standard and operating requirement of users.

In this paper, it is studied the effects of main chemical elements P and Ti in ultra-low carbon deep drawing steel as well as main production technologies (i.e. cooling mode of hot rolling, annealing temperature and annealing speed) on strength of steel strip. The yield ratio of steel strip is reduced, punch formability is improved through optimizing the performances of DC04 of Baotou Steel according to customer requirements so that they could be met.

In the paper, the effects of different hardening and tempering technologies on mechanical properties of 27SiMn seamless steel tube for hydraulic support are studied. The results showed that the yield strength and tensile strength of 27SiMn test steel were gradually decreasing as well as its impact work and elongation were on the rise with temper temperature increased within the range of 580~680 ℃; the comprehensive mechanical properties could meet the requirements of user's technology agreement, batch production was realized and performances were stable when temper temperature was 610~630 ℃.

In this paper, it is introduced the experimental study on high temperature plasticity of GCr15 steel, compared and analyzed its interior surface quality at different perforation temperatures. The experimental results showed that the plasticity of GCr15 steel was good at 850~1 200 ℃, the main reason for infolding of internal surface for steel tube was that perforation temperature of tube blank was beyond high temperature plastic range and it could be reduced if perforation temperature could be controlled within 1 200 ℃.