In order to investigate the effects of different rare earth additions and different heat treatment processes on the properties of rare earth protective steel BT700E, in the laboratory, the pilot test with rare earth alloy adding quantity 5 × 10^-6, 10 × 10^-6 and 15 × 10^-6 are carried out, and different heat treatment systems are matched, and the heat treatment process with 880℃ quenching temperature and 560 ℃, 580 ℃ and 600 ℃ tempering temperature are respectively carried out. The effects of different rare earth additions and different heat treatment systems on the properties of test steels are compared, and results show that the 10 × 10^-6 rare earth addition, 880 ℃ quenching + 580 ℃ tempering in heat treatment process, mechanical properties can meet the requirements of SSAB related technical specifications.

X65 pipeline steel is mainly used in the manufacture of oil and gas pipelines, requiring high strength, high toughness, brittle fracture and good welding performance, but it is easy to appear slab defects in the continuous casting process, which will reduce the comprehensive performance of pipeline steel. In the paper, the high-temperature plasticity of X65 pipeline steel slab is studied. The hot tensile test is carried out by using Gleeble-1500D thermal simulation testing machine, and under the strain rate of 2.0 × 10^-3/s, deformation temperature of 700~1 300 ℃, the fracture strength and the section shrinkage change with temperature are analyzed. The fracture morphology is observed by scanning electron microscope, and the cause of fracture is clarified to provide a theoretical basis for continuous casting production.

The square Q235B plates which are perpendicular to the rolling direction are bent to different degrees by WDW-200 kN universal testing machine, and the relationship between grain size variation, dislocation movement and neutral layer are studied. The results show that microstructure evolves from lath grain into equiaxed grain, and with neutral layer as the boundary, the outer layer thickness is thinner under the action of external tension when the plate is bent, the thickness of the inner layer increasing under pressure, and under the maximum deflection, the increase of r/t specimen is not easy to crack.

Based on the design philosophy of ERP system in Rare Earth Steel Plate plant, giving full play to the advantages of steel GA, GK and GE composition control, successfully achieving the effective combination of steel grade Q235A, Q235B and SS400, after the merger, the three steel grades are designed with one component by using TMCP (thermomechanical control) technology, that is, the rolling and cooling process adjustments, which achieves flexible rolling of Q235A, Q235B and SS400. From the experimental point of view, the feasibility of intensive production technology is verified. By means of flexible rolling technology, the difficulty of smelting is largely simplified, and the fluctuation of steelmaking components is effectively controlled.

In the paper, aiming at the problems existing in the tank floor flaw detection, it is proposed to take nondestructive testing for tank floor by using shear wave probe exciting ultrasonic guided-wave. Ultrasonic guided wave as a new nondestructive testing method, has solved the difficulties in the detection of tank floor defects in China to a great extent. The paper explains the basic concept of guided waves, analyzes the feasibility of nondestructive flaw detection for tank floor by using shear wave probe exciting ultrasonic guided-wave, and determines the parameters and characteristics of using shear wave probe exciting ultrasonic guided-wave. ANSYS is used to make fem simulation of guided wave tank floor defect detection, and the conclusion that SH0 mode guided wave can be excited by using shear wave probe and the defect can be detected are obtained.

19JC digital universal tool microscope is a kind of two-dimensional coordinate measuring instrument widely used in the machining production. However, the tool microscope involves optical and geometrical measurement, the multi parameter and high precision of equipment, which leads to the tedious process, low work efficiency and great accidental error. According to the automatic measuring system of advanced tool microscope both at home and abroad, the existing 19JC digital universal tool-measuring microscope was systematically upgraded and succeeded by using CCD camera technology, digital image processing technology and grating detection technology.

The total amount of rare earth in mixed rare earth chloride solution [RECl₃(L)] is determined by EDTA titration and the effects of glass metering instruments, analytical reagents, sample homogeneity and non-rare earth metal ions on the measurement results are studied. The results show that: Glass metering instruments have the greater impact on the measurement results, especially the error accumulation effect of metering instruments, and errors of total rare earth correction (within the maximum allowable calibration error) can reach 3.66 g/L; the effect of aluminum and iron ions on the measurement results can be eliminated by adding masking agents; the zinc ion concentration is small and the effect on the results can be negligible. In the daily analysis process, pay attention to analyze the quality and correct use of reagents, ensuring the homogeneity of samples, reducing the analysis error, and improve the accuracy of analysis results.

In the paper, according to the situation of low efficiency and unstable system for hot rolled coil pallet conveying system after officially put into use, and from multi-angle analysis in actual field situation, rectification and reform programs are put forward, at the same time achieving good results in actual system transformation, which better meets the needs of fast-paced production in hot rolling.

On the basis of satisfying the profile steel production process in Rail and Beam Plant of Baotou Steel, the existing problems are analyzed and according to the specific performance in actual production, from the palletizing hardware system and control program, replace the encoding disk and motor, optimizing the motor internal contracting brake, resetting the frequency converter and other key equipment, rewriting the palletizing program to meet the variety of rolling requirements, which solve the problem of being necessary to write the corresponding program when rolling a new variety.

Aiming at the AC-AC variable-frequency speed control system of heavy plate mill main drive in Baotou Steel, the calculation method of DC current regulator of SIEMENS AC-AC frequency converter is studied. The calculation method is simple, the calculation of regulator is optimized, the operation performance of system is improved, the safety and stability of production and operation of main drive system are improved, and the application effect is good.