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The material selected for this investigation was low alloy weld metal deposit after TIG welding with various amount of oxygen in weld metal deposit (WMD). After TIG process it is difficult to get proper amount of oxygen in WMD on the level much lower than 350 ppm. The highest impact toughness of low alloy WMD corresponds with the amount of oxygen in WMD above 350 ppm. In the paper focuses on low alloy steel after innovate welding method with micro-jet cooling that could be treated as a chance on rising amount of oxygen in weld. Weld metal deposit (WMD) was carried out for TIG welding with micro-jet cooling with various amount of oxygen in WMD. In that paper various gas mixtures (gas mixtures Ar-O2 and Ar-CO2) were tested for micro-jet cooling after TIG welding. An important role in the interpretation of the results can give methods of artificial intelligence.

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 Ms at 430.6°C. Despite very rapid cooling times t8/5 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.

Thermally spraying with micro-jet cooling is an innovate technology. It is possible to get fine dispersive structure of coatings during the shorter time in comparable to the classical high velocity oxygen fuel process (HVOF). It corresponds with good corrosion-erosion properties of structure. In the paper the parameters of the spraying with micro-jet cooling process are presented. The selected properties of coatings obtained by hybrid method are presented. The results of wear tests for hybrid and HVOF coating are compared. Results of investigation are very optimistic. The presented technology should be adapted to the actual production of protective coating for machines and construction working in wear conditions.

The paper focuses on low alloy steel after innovate welding method with micro-jet cooling. Weld metal deposit (WMD) was carried out for welding and for MIG and MAG welding with micro-jet cooling. This method is very promising mainly due to the high amount of AF (acicular ferrite) and low amount of MAC (self-tempered martensite, retained austenite, carbide) phases in WMD. That structure corresponds with very good mechanical properties, ie. high impact toughness of welds at low temperature. Micro-jet cooling after welding can find serious application in automotive industry very soon. Until that moment only argon, helium and nitrogen were tested as micro-jet gases. In that paper first time various gas mixtures (gas mixtures Ar-CO2) were tested for micro-jet cooling after welding.

The material selected for this investigation was low alloy steel weld metal deposit (WMD) after MIG welding with micro-jet cooling. The present investigation was aimed as the following tasks: obtained WMD with various amount of acicular ferrite and further analyze impact toughness of WMD in terms of acicular ferrite amount in it. Weld metal deposit (WMD) was first time carried out for MIG welding with micro-jet cooling of compressed air and gas mixture of argon and air. Until that moment only argon, helium and nitrogen were tested as micro-jet gases for MIG/MAG processes. An important role in the interpretation of the results can give methods of artificial intelligence.

This paper presents results of experimental research concerning the impact of an innovative method of micro-jet cooling on the padding weld performed with MIG welding. Micro-jet cooling is a novel method patented in 2011. It enables to steer the parameters of weld cooling in a precise manner. 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 material under study was steel 20MnCr5, which was subject to the welding process with micro-jet cooling and without cooling. Nitrogen 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. The following results exhibit growth at approximately 5% in wear resistance of padding welds with micro-jet cooling.

The paper provides a comprehensive presentation of the influence of operating parameters on the tribological properties of the wheel-rail couple. Apart from wear and a friction coefficient, the tribological properties also comprise stereological parameters of flaky wear products. The tribological tests were carried out according to an experimental plan, which took account of the complex influence of operational factors on the size and shape of flaky wear products. This enabled defining the type and intensity of wear, depending on the variable operational parameters. In order to explain the wear mechanism, quantitative, qualitative, and profilographometric metallographic examinations were made.

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.

The innovative technology, like thermal spraying with a micro-jet cooling is one of the important modification of classical ultrasonic spraying methods. Using of micro-stream with gases like argon or nitrogen allows to cool the coating immediately after spraying, and thereby reduce the time of transition during the injection of each layer. As a result of the process, the fine dispersive structure of coatings is obtained during the shorter time in comparable to the classical high velocity oxygen fuel process (HVOF). The parameter of process and the type of stream equipment determine the quality of the obtained structure and thermal stress in the coating. The article presents the relationship between selected parameters of hybrid process and properties of the coatings. The presented technology should be adapted to the actual production of protective coating for machines and construction working in wear conditions.

The material selected for this investigation was low alloy steel weld metal deposit (WMD) after MAG welding with micro-jet cooling. The present investigation was aimed as the following tasks: analyze impact toughness of WMD in terms of micro-jet cooling parameters. Weld metal deposit (WMD) was first time carried out for MAG welding with micro-jet cooling of compressed air and gas mixture of argon and air. Until that moment only argon, helium and nitrogen and its gas mixture were tested for micro-jet cooling.

Low carbon steel weld structures generally exhibit a very linear stress-strain relationship. In the study of strength of materials, the compressive strength is the capacity of a material or structure to withstand loads tending to reduce size of structure. It is mainly measured by plotting applied force against deformation in a testing machine. Compressive strength is a main key value for design of welded structures.The main goal of that paper was analysing of plastic properties of frame welds which were made with various parameters of micro-jet cooling. New technology of micro-jet welding could be regarded as a new way to improve plastic properties of welds. It allows to obtain welds with better mechanical properties in comparison to ordinary welding method. Furthermore it is possible to steering of weld structure and properties of the weld. There were given main information about influence of various micro-jet gases on metallographic and properties of structure steel welds.

The paper presents results of research tribological properties laser hardened steel 42CrMo4. Parameter influencing on the quality of the hardened surface was laser head speed. The study was conducted on friction tester pin-on-disc type T-11, and a counter sample disc was silicate. Parameter determining the quality of the surface layer is the intensity of wear. Based on the results we obtain information about the laser head speed to temper steel 42CrMo4 so as to maintain a high resistance to wear.

A paper presents a piece of information about innovate surfacing technology with micro-jet cooling. There are put down information about parameters of shaft surfacing with micro-jet cooling process. There were given information about influence of various micro-jet gases on metallographic structure of machine shaft after surfacing. There were analyzed tribological properties of welds. Welding surfacing process is very often used to apply a hardness or wear-resistant layer of base metal. It is very important method of extending the life of machines, tools, and construction equipment. Surfacing is also known as wearfacing, is often used to build up shafts, gears or cutting edges. Regenerated surface properties of various machine elements do not provide good tribological properties. The tribological interactions of a solid shaft surfaces were tested after welding with micro-jet cooling.

The main goal of that paper was analysing of plastic properties of welds made with micro-jet cooling. New technology of micro-jet welding could be regarded as a new way to improve plastic properties of welds. It allows to obtain welds with better properties in comparison to ordinary welding method. Moreover, it is possible to steering of weld structure and properties of the weld. During research Erichsen cupping tests and bending tests were carried out for welds made by MIG method with micro-jet cooling. Argon was cooling medium. Different numbers of micro-jet streams were used to weld cooling. Different plastic properties were obtained for different numbers of micro-jet streams. In this research welds made by new method of welding (welding with micro-jet cooling) were compared with welds made by ordinary welding method.

Micro-jet cooling after welding was tested only for MIG welding process with argon, helium and nitrogen as a shielded gases. A paper presents a piece of information about nitrogen and oxygen in weld after 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 main information about influence of various micro-jet gases on metallographic structure of steel welds. Mechanical properties of weld was presented in terms of nitrogen and oxygen amount in WMD (weld metal deposit).

Micro-jet welding is an innovative method of weld forced cooling immediately after welding. It allows to obtain weld with superior properties in comparison to conventional welding. The reason for this is to obtain a more favorable structure of the weld metal deposit (WMD) with much higher amount of acicular ferrite (AF). Different structures and mechanical properties of weld metal deposit were obtained by using various gases for cooling. The paper shows the relationship between the type of gas for micro-jet cooling and plastic properties of the weld joint. Coefficient of restitution and plastic strain were selected to describe changes of weld plastic properties for different micro-jet cooling gases. The tests were performed in dynamic conditions (impact).

Celem badań było określenie rzeczywistego wpływu stopnia chropowatości powierzchni pojemnika na plastyczne płynięcie metalu w procesie współbieżnego mikrowyciskania pręta metalowego. Do badań użyto zestawu narzędziowego autorskiego projektu oraz wyżarzonego, aluminiowego drutu o średnicy 1.7 mm, dla którego wyznaczono charakterystykę materiałową. Zestaw składa się z dwóch modeli pojemników na wsad i prostokątnych matryc o tych samych wymiarach, różniących się stopniem chropowatości. W celu wyznaczenia stopnia chropowatości warstw wierzchnich pojemników na wsady dla każdego z nich wyznaczono profile z użyciem mikroskopu laserowego. W trakcie przeprowadzania prób współbieżnego wyciskania wyznaczono przebiegi ciśnień na stemplu dla poszczególnych próbek a następnie zarejestrowano deformacje linii równoległych naniesionych na przekrojach wzdłużnych wyciśniętych elementów. Otrzymane próbki poddano testom mikrotwardości. Następnie wykonano numeryczną analizę analogicznych procesów mikrowyciskania. Chropowatość pojemników zamodelowano w formie sztywnej trójkątnej fali z zerowym współczynnikiem tarcia na kontakcie m = 0. Wyznaczono kształty siatek de- formacyjnych wyciśniętego materiału oraz ciśnienia na stemplach. Przeprowadzone badania ujawniły możliwość wytwarzania wyrobów o różnych właściwościach mechanicznych, uzyskiwanych poprzez dobór określonej chropowatości narzędzia.

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.

Laser jest szeroko stosowany w mikro-spawaniu. Oprócz tej metody, spawanie z chłodzeniem mikrojetowym powinno być traktowane jako ważna metoda spawania cienkościennych konstrukcji. W artykule przedstawiono innowacyjną technologię spawania z chłodzeniem mikrojetowym w porównaniu do spawania laserowego. Uzyskano informacje o wpływie obu metod na strukturę metalograficzną stalowych cienkościennych konstrukcji. Zawartość ferrytu AF była porównana w obu przypadkach.

Weld metal deposit (WMD) was carried out for standard MMA welding process. This welding method is still promising mainly due to the high amount of AF (acicular ferrite) and low amount of MAC (self-tempered martensite, retained austenite, carbide) phases in WMD. That structure corresponds with good impact toughness of welds at low temperature. Separate effect of these elements on the mechanical properties of welds is well known, but the combined effect of these alloy additions has not been analyzed so far. It was decided to check the total influence of nickel with a content between 1% to 3% and molybdenum with content from 0.1% up to 0.5%. [ABSTRACT FROM AUTHOR]

The paper offers mathematical equations of the influence of micro-jet cooling on structure and impact toughness properties of metal weld deposit. Weld metal deposit (WMD) was carried out for standard MIG welding and for MIG welding with micro-jet cooling. This new method is very promising mainly due to the high amount of AF (acicular ferrite) and low amount of MAC (selftempered martensite, retained austenite, carbide) phases in WMD. That structure corresponds with very good mechanical properties ie. good impact toughness of welds at low temperature. Micro-jet cooling after welding can find serious application in automotive industry very soon. Until that moment only argon, helium, nitrogen and gas mixtures of argon were tested for micro-jet cooling after welding. The best results of mechanical properties of WMD in presented welding method correspond with micro-jet argon cooling. [ABSTRACT FROM AUTHOR]

During metal bulk-forming in microscale the socalled size effect, making changes in the material deformation process should be taken into account. One of the factors having a significant influence on the flow mechanics is a die roughness. Paper contains results of numerical analysis of the cylindrical sample compression between anvils with sinusoidal profile of roughness and with zero friction factor at the tool-workpiece interface in dry conditions. Two models of dies were used: parallel and conical one. Obtained data were compared to analogous, conventional models of compression tests with flat dies and with constant friction factor - equivalent to sinusoidal wave. Sinusoidal curve modeling the die roughness was determined from the surface roughness profile and using the motifs method. Presented analysis revealed increase in value and in variability of stress and strain in layers flowing in the vicinity of the wave - size effect. No impact of the wave presence on the compression forces values was obtained. [ABSTRACT FROM AUTHOR]

The article analyses an effect of paper strain rate on energy absorbed during tensile testing. The tests were carried out in the range where the effect of inertia forces could be omitted. A new calculation method is proposed to predict variations in breaking energy caused by changes in strain rate. The method was verified by laboratory tests and calculation results and its practical usefulness was confirmed. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Investigation results presented in the work relate to the impact of tool roughness on the material plastic flow during forward microextruding of metal. Investigation process consists of the experimental and numerical parts. In the experimental one, forward microextrusion of annealed material using the toolkit author's copyright project was performed. The tests were conducted to compare deformation of the material extruded in containers with different roughness. As a result, obtained images of deformed material structures are presented and compared. Numerical part relates to simulations of analogous microextrusion processes conducted using DEFORM software. Tool roughness was modeled in the form of rigid triangular waves, whose geometric parameters were based on the roughness profiles obtained for the experimental tools. Depth and length of the triangular elements were determined using the motives method. Distribution fields of the effective stress, strain and the flow velocities are presented and compared. Based on obtained data, concept of determining of the parameter which can help to define the appearance of structural size effect resulting from the influence of container roughness is also presented. [ABSTRACT FROM AUTHOR]