An article presents actual information about innovate welding technology with micro-jet cooling. There are put down information about gases that could be chosen for micro-jet process. There were given information about influence of various micro-jet gases on metallographic structure of steel welds.Keywords: welding, micro-jet cooling gases, weld, metallographic structure, acicular ferrite W artykule przedstawiono innowacyjną technologię spawania z chłodzeniem mikro-jetowym. Podano informacje nt gazów, które mogą być wybrane dla mikro-jetowego procesu. Uzyskano informacje o wpływie doboru gazu mikro-jetowego na strukturę metalograficzną stalowych spoin.

The article presents results of investigations on autogenous laser welding of new grade STRENX 1100 MC steel. The modern Disk laser was applied for of 5.0 mm thick butt joints welding. The influence of laser welding parameters, mainly the energy input of laser welding on the penetration shape, weld quality, structure and mechanical performance was investigated. It was found that the investigated steel has surprisingly low carbon equivalent CET just 0.328, and also relatively high temperature of martensitic transformation M s at 430.6°C. Despite very rapid cooling times t 8/5 in a range from 0.6 to 1.3 s, thus rapid solidification there was no tendency to cracking of weld metal or HAZ. Significant drop of microhardness in the HAZ resulted in a decrease of tensile strength of joints, compared to the base metal. Impact toughness of test joints was at only 50÷60% of the base metal.

Low alloy steel is used for many important structures. In that material there is a small amount of carbon and controlled percentage of alloy elements such as Ni, Mn, Mo, Si in steel and welded joints. Especially Ni, Mo, O could be treated as elements positively influencing impact toughness of welded structures. Metallographic structure of weld metal deposit (WMD) having composition of 400 ppm O and 2% Ni or 0.4% Mo and is very beneficial because of high percentage of acicular ferrite (until 65%) and thus WMD has good mechanical properties. For a long time researchers were putting two questions: how to lift percentage of AF in weld, and further what consequence that fact gives? Micro-jet technology could be treated as a chance to resolve that problem. The present paper describes the influence of artificially lifted amount of acicular ferrite in WMD (above 65%) on the behaviour of steel weld properties using micro-jet cooling.Keywords: micro-jet cooling, weld, metallographic structure, acicular ferrite, impact toughness Do ważnych konstrukcji używana jest stal niskostopowa, bardzo często z małą ilością węgla i kontrolowana zawartością pierwiastków stopowych, takich jak Ni, Mn, Mo, Si. Zwłaszcza Ni, Mo, O są uważane za pierwiastki pozytywnie wpływające na udarność spawanych konstrukcji. Struktura metalograficzna stopiwa posiadającego 400 ppm O i 2% Ni albo 0,4% Mo korzystnie wpływa na własności mechaniczne złącza z powodu wysokiej zawartości drobnoziarnistego wewnątrz-ziarnowego ferrytu (ferryt AF) w stopiwie (do 65%) i przez to na dobre własności mechaniczne. Przez długi czas badacze zadają dwa pytania: jak można podnieść zawartość ferrytu AF w spoinie i jakie to przyniesie następstwa? Technologię microjetową uważa się za szanse na rozwiązanie tego problemu. Przedstawiony artykuł opisuje wpływ sztucznie zawyżonej zawartości ferrytu AF w stopiwie (ponad 65%) na właściwości stalowego złącza ze względu na zastosowanie mikrojetowego chłodzenia.

In order to improve the tribological properties of titanium alloy Ti6Al4V composite surface layers Ti/TiN were produced during laser surface gas nitriding by means of a novel high power direct diode laser with unique characteristics of the laser beam and a rectangular beam spot. Microstructure, surface topography and microhardness distribution across the surface layers were analyzed. Ball-on-disk tests were performed to evaluate and compare the wear and friction characteristics of surface layers nitrided at different process parameters, base metal of titanium alloy Ti6Al4V and also the commercially pure titanium. Results showed that under dry sliding condition the commercially pure titanium samples have the highest coefficient of friction about 0.45, compared to 0.36 of titanium alloy Ti6Al4V and 0.1-0.13 in a case of the laser gas nitrided surface layers. The volume loss of Ti6Al4V samples under such conditions is twice lower than in a case of pure titanium. On the other hand the composite surface layer characterized by the highest wear resistance showed almost 21 times lower volume loss during the ball-on-disk test, compared to Ti6Al4V samples.

OXYGEN IN STEEL WMD AFTER WELDING WITH MICRO-JET COOLING TLEN W STALOWYM STOPIWIE PO SPAWANIU Z CHŁODZENIEM MIKROJETOWYMUntil that moment micro-jet technology was tested only for MIG welding process with argon as a shielded gas. An article presents actual information about innovate welding technology with micro-jet cooling. There are put down information about gases that could be chosen both for MIG/MAG welding and for micro-jet process. There were given information about influence of various micro-jet gases on metallographic structure of steel welds. Mechanical properties of weld was presented in terms of oxygen amount in WMD (weld metal deposit).Keywords: welding, micro-jet cooling gases, weld, metallographic structure, acicular ferrite Dotychczas technologia mikrojetowa była stosowana tylko w spawalniczym procesie MIG, gdzie gazem osłonowym był argon. W artykule przedstawiono innowacyjną technologię spawania z chłodzeniem mikrojetowym. Podano informacje zarówno dla gazów, które mogą być wybrane dla spawania MIG/MAG i dla mikrojetowego procesu. Uzyskano informacje o wpływie doboru gazu mikrojetowego na strukturę metalograficzną stalowych spoin. Własności mechaniczne złącza podano w funkcji zawartości tlenu w stopiwie.

In this paper are presented the results of experimental studies determining the dependence of the impact of an innovative welding micro-jet method on the intensity of abrasive wear of chrome-manganese 20MnCr5. The presented method is generally used for the constructions work items matrix for the production of silicate. The results confirm that the micro-jet welding method reduces the abrasive wear intensity of about 20% compared to the steel after thermo-chemical treatment. Other parameters such as the friction coefficient and power friction show comparable value, and therefore do not have a significant impact on working conditions.

The paper presents the characteristics of innovative technology of micro-jet cooling in MIG welding (according to PN-EN ISO 4063:2009). Presented results received at different jet hole geometry and various coolant pressure. This technology allows get, with appropriately selected parameters of cooling increased ferrite AF content in weld metal, up to 14% for standard MIG technology. This structure proves toughness, especially at temperature -40• C. Keywords: micro-jet cooling, weld, metallographic structure, acicular ferrite, impact toughness W pracy scharakteryzowano innowacyjną technologię chłodzenia mikrojetowego podczas spawania metodą MIG (zgodnie z normą PN-EN ISO 4063:2009). Przedstawiono wyniki badań uzyskanych przy różnych ustawieniach geometrycznych otworów chłodzących oraz różnym ciśnieniu medium chłodzącego. Zastosowanie tej technologii pozwala uzyskać, przy odpowiednio dobranych parametrach chłodzenia większą zawartość ferrytu AF w stopiwie, do 14% w odniesieniu do standardowej technologii MIG. Ma to wpływ na udarność, szczególnie przy temperaturze -40• C.

An article presents information about innovate welding technology (surfacing) with micro-jet cooling. There are given main information about parameters of shaft surfacing with micro-jet cooling process. There were also put down information about influence of various micro-jet gases on metallographic structure of machine shaft after surfacing. There were tested tribological properties of welds. The tribological interactions of a solid shaft surfaces were tested after welding with micro-jet cooling.