J. Piwnik

Structure and Properties of Steel Welding after Micro-Jet Cooling Process

Welding with micro-jet cooling is an innovate technology. It is possible to get structure of weld metal deposit (WMD) with a very high amount of acicular ferrite (on the level of 70 %) that is not valuable for other processes. It corresponds with good impact toughness of weld. In the paper parameters of micro-jet cooling and mechanical structure of weld will be present and compared with welding without micro-jet cooling. Results of investigation are very optimistic. That technology should be treated for welding of other materials.

The Composite Materials for High Erosion Resistance Coatings Applied in Power Industry

The article presents the issues related to composite materials and the fabrication process of protective coatings by thermal spraying methods used for the protection of power plant boiler elements . The basic composite materials for thermal spraying process were characterized. The presented materials allow produced the erosion-corrosion resistant coatings. The chemical composition, phase structure and properties of the selected materials are presented. The basic group of coatings with the high corrosion and erosion resistance are produced by thermal spraying method, like HVOF (High velocity oxy fuel). In this article the selected properties of composite materials sprayed by innovative technology are characterized.

THE IMPACT OF GAS ON THE TRIBOLOGICAL PROPERTIES OF STEEL 16MnCr5 AFTER SURFACING WITH MICRO-JET COOLING

This paper presents results of experimental research concerning the impact of an innovative method of micro-jet cooling on the padding weld performed with MAG welding. It enables to steer the parameters of weld cooling in a precise manner. Micro-jet cooling is a novel method patented in 2011. In addition, various elements, which may e.g. enhance hardness or alter tribological properties, can be entered into its top surface, depending on the applied cooling gas. The micro-jet welding method is the innovative method, which reduces the intensity of abrasive wear. The method can be used as a basic finishing or a regeneration method. An innovative technology for micro-jet is used to cool the weld surface that is, using a micro-welding jet cooling. This allows accurate and complete control of the surface structure of the deposit. The material under study was steel 16MnCr5, which was subject to the welding process with different gases of micro-jet cooling. Nitrogen and air was used as a cooling gas. The main parameter of weld assessment was wear intensity. The tests were conducted in a tribological pin-on-disc type position. T-11 pin-ondisc tester allows for indicating basic wear parameters (wear intensity, wear coefficient, wear force). Based on results of experiment the application of nitrogen in micro-jet cooling of the padding weld in the welding process of steel 16MnCr5 beneficially affects resistance to abrasive wear.

Optimization of Micro-Jet Selective Cooling After Low Alloy Steel Welding

The paper focuses on low alloy steel after an innovative welding method with selective micro-jet cooling. Weld metal deposit (WMD) was carried out for MIG process with micro-jet cooling. This method is very promising mainly because of the high amount of acicular ferrite in low alloy steel WMD. That structure corresponds with high impact on the toughness of welds. Dynamical systems of micro-jet cooling just after welding can find application in automotive industry.