Charpy Impact Behavior of a Novel Stainless Steel Powder Wire Mesh Composite Porous Plate

A novel powder wire mesh composite porous plate (PWMCPP) was fabricated with 304 stainless steel powders and wire mesh as raw materials by vacuum solid-state sintering process using self-developed composite rolling mill of powder and wire mesh. The effects of different mesh volume fractions, mesh diameters, and sintering temperatures on the pore structure and Charpy impact properties of PWMCPPs were studied. The results show that PWMCPPs have different shapes and sizes of micropores. Impact toughness of PWMCPPs decreases with increasing wire mesh volume fraction, and increases first and then decreases with increasing wire mesh diameter, and increases with increasing sintering temperature. Among them, the sintering temperature has the most obvious effect on the impact toughness of PWMCPPs, when the sintering temperature increased from 1160 °C to 1360 °C, the impact toughness increased from 39.54 J/cm2 to 72.95 J/cm2, with an increased ratio of 84.5%. The tearing between layers, the fracture of the metallurgical junction, and the fracture of wire mesh are the main mechanisms of impact fractures of the novel PWMCPPs.

Influence of introduction of titanium into the composition of a powder wire of type 25X5FMS

The effect of titanium introduction on the microstructure and physical and mechanical properties of metal deposited with flux-cored wire 25X5FMS has been studied. Surfacing of the investigated samples was carried out using a flux made from crushed slag produced by silicomanganese. The microstructure and non-metallic inclusions in the deposited layer have been studied. It is shown that with an increase in the concentration of titanium in the deposited metal, the hardness increases and the wear decreases.

Scale resistance increase in hot rolling rollers by powder wire welding deposition

The application of PP30N8H6M3STYu powder wire is considered which ensures high scale-resistance of welded metal. It is defined that the scale formation indices of 30N8H6M3STYu metal are much better than those in 30H2V8F steel at the temperature of 900ºC. It is shown that the scale base of 30N8H6M3STYu metal is chemical compounds of Fe2O3, Fe3O4, Cr2FeO4, Fe2NiO4 and Fe3N.

PROSPECTS FOR THE APPLICATION OF LASER SURFACE TECHNOLOGY FOR RESTORING ROLLERS OF CONTINUOUS CASTING MACHINES

The article considers the possibility of applying laser cladding technology to restore the rollers of continuous casting machines. Effective methods of restorative surfacing of rollers of continuous casting machines are briefly presented. The paper describes the process of forming coatings for rollers using laser and electric arc surfacing methods. Laboratory equipment for preparing experimental samples for metallographic studies is described. The method of preparation of laboratory samples of coatings obtained by laser and electric arc surfacing is described. Electric arc surfacing of 20X13 steel samples is performed with PP-NP-25X5FMS powder wire. Laser surfacing of samples made of 20X13 steel is performed with an economically alloyed powder based on Fe-Co-Cr-Mo iron. The structure and composition of surfaced coatings by electric arc and laser surfacing methods for rollers of continuous casting machines are studied. The mechanical properties of the applied coatings for the rollers are studied. Tribological characteristics of coatings applied by electric arc and laser surfacing methods are investigated. To evaluate the properties of coatings, a structural and phase analysis is performed, and the friction coefficients and wear rate are determined. Graphic images of the deposited layer structures are presented. The dependences of the friction coefficient of the deposited layers are presented and their differences for each of the surfacing methods are analyzed. An explanation of the differences in the properties of coatings based on the analysis of their formation conditions is offered. The efficiency of using the laser surfacing method for restoring parts of metallurgical equipment is evaluated.

Thermal treatment impact upon structure, properties and phase structure of steel 10G7M3S2AFTYu weld with powder wire

There are investigated peculiarities of hardening through ageing of steel 10G7M3S2AFTYu weld with powder wire. It is defined that ageing at the temperature of 550ºC during 6 hours ensures the highest degree of strengthening of ferrite steel 10G7M3S2AFTYu. It is proved that the mechanism of steel strengthening as a result of ageing is determined with the Ti2CN, V1.98Ti0.02, VC combinations mainly.

Development of self-protective powder wire with diameter of 1.6 mm for automatic welding of pipe-lines joints root

The results of self-protective powder wire with diameter of 1.6 mm are presented. The working purpose is to create small-section powder wire and its manufacturing technology, designed for automatic welding of the root layer of the seam of non-rotating joints of main pipe-lines transporting oil and gas with admixture of hydrogen sulfi de, and providing increase of at least 1.5 times the productivity of pipe welding. The forming rollers for the initial billet with diameter of 2.4 mm of two-bend powder wire are developed. The composition of the charge fl uxcored wire, providing the requirements of product development: reliable penetration of the root layer of the seam fi xed joints of pipe-lines with tensile strength of the weld metal at 490 MPa. Recommendations on the production technology of self-protective powder wire of two-bend design are developed.

Technological increase of adhesive wear-resistance of parts added with chromium powder wire alloyed with complex of boron and nitrogen compounds

It is shown that the structure of metal padded with powder wire having the following mixture: 15% Cr – 0,5% B4C – 0,5% BN – 2,5% TiB2 – 1,0% ZrB2, is a martensitic matrix with (Fe, Cr)2B boride eutectic, carbon boride of (Fe, Cr)7(C, B)3 type and ε –(Fe, Cr)2-3N nitrides. Such a wire can be used for strengthening weld deposition of parts operated under conditions of heavy friction loading.