Ультразвуковой контроль сварного шва тонкостенной титановой оболочки с индикатором непровара

The work considers the methodology of weld ultrasonic inspection of thin-wall (0.6 mm) titanium alloy shells. The paper also presents a review of publications on Lamb wave excitation and propagation, and on applications of ultrasonic inspection of thin-wall weldments. The problem of adhesion detection was successfully solved (weld zones with incomplete fusion conduct ultrasonic waves well, but do not provide mechanical strength). Angular groove is proposed as an indication of incomplete fusion in the weld. We analyzed different propagation modes of Lamb wave in the material and selected optimum inspection parameters. Wavelet analysis and precise digital filters with small increment provided great efficiency. Inspection results of corrupted weld and defect-free regions were analyzed. The results of ultrasonic scanning were compared to metallographic study data.

Selective Laser Melting of Stainless Steel with Subsequent Processing

In this work we describe the results of selective laser melting of stainless steel. The obtained samples were processed by hot isostatic pressing. Metallographic study of samples obtained after selective laser melting and hot isostatic pressing procedure was conducted. Comparison of the structure of obtained samples and a significant decrease in porosity after hot isostatic pressing was registered. The results of the phase composition by X-ray diffractometry are presented. Identified significant structural and phase changes at the study of a surface of the obtained microsections of samples, and a change in the hardness of the samples were recorded.

An Investigation of Ingots Teemed under Different Thermal and Physical Solidification Conditions and the Analysis of Metal Quality of the Hollow Forgings Produced

Optical and electron microscopy are used in the paper to analyze the quality of the cast metal of a 1.53 ton ingot of steel 38ХН3МФАteemed with a cooling feeder head. In addition, the analysis of the metal of hollow forgings produced from ingots with “cooled” and thermally insulated feeders is performed. A metallographic study reveals that if the ingot top is cooled down, it results in an accelerated solidification throughout the entire mass of the ingot; in addition, the thermal centre shifts to the ingot central axial area.