In the laser treatment of a workpiece (9), e.g. for surface hardening, melting, alloying, cladding, welding or cutting, the adverse effect of reflectivity of the surface, when a pure, monochromatic laser (6) is used, is remedied by the simultaneous application of a relatively shorter wavelength beam (1). The two beams (1)(5) may be combined by a beam coupler (4) or may reach the workpiece (9) by separate optical paths (not shown). The shorter wavelength beam (1) improves the coupling efficiency of the higher- powered laser beam (5).

Laser Material Processing

Some mechanical properties of borided AISI H13 and 304 steels

The state of laser processing in surface materials modification in Poland is reported, based on own experience, coworkers and coauthors results, as well the literature review. The curriculum concerning historical development of lasers and laser technology in Poland, laser-matter interaction, as well basis of different laser techniques applied in materials surface engineering (solid state hardening, melting, alloying, cladding, ablation, shot peening, cleaning and texturing) are reviewed, and compared with results of coauthors, as well with a wide range of Polish authors papers. Finally, it is concluded that overall state of research on laser application in surface engineering in Poland is well developed and still growing industrial application is observed.

https://journals.pan.pl/Content/83650/PDF/paper_06.pdf

Laser modification of the materials surface layer – a review paper

Boriding kinetics of H13 steel

Boronizing of an XC38 steel was performed by immersion in molten salts. These were based on a borax containing three reducing agents: boron carbide (B 4 C), aluminium (Al) and silicon carbide (SiC). This work gives a survey on the nature and quality of the layers which were obtained according to the boronizing bath. The mechanical features (hardness, scratch and wear resistance) of the deposited layers are discussed according to the experimental conditions used for their characterization. Effects of the boronizing bath composition on the obtained layers' quality are also discussed. According to the borax's reducing agents, the boronized layer deposited on the XC38 steel was either single- or double-phase. Al and B 4 C led to double-phased boronized layers, whereas SiC gave way to a single-phase layer. All the layers were of comparable hardness which was about 2100 HV on the samples for the boride FeB and 1800 HV for the boride Fe 2 B. The scratch and “pin-on-disk” wear resistance depended on the layers' microstructure. The best values of scratch and wear resistance were obtained for SiC which led to the formation of a single-phase layer. The apparition of scaling occurred at loads superior to 200 N.

Characterization of boronized layers on a XC38 steel

Microstructure and properties of borided 41Cr4 steel after laser surface modification with re-melting

Characterization of complex (B + C + N) diffusion layers formed on chromium and nickel-based low-carbon steel

The importance of carbon content beneath iron borides after boriding of chromium and nickel-based low-carbon steel

Combined surface hardening with boron and carbon was used for low-carbon 5120 steel. The microstructure, carbon profiles and chosen properties of borided layers produced on the carburized 5120 steel have been examined. These composite (B + C) layers are termed borocarburized layers. The microhardness profiles and wear resistance of these layers have been studied. In the microstructure of the borocarburized layer two zones have been observed: iron borides (FeB + Fe2B) and a carburized layer. It has been found the depth (100–125 μm) and microhardness (1500–1900 HV) of iron borides zone. The carbon content (0.83–1.46 wt pct) and microhardness (950 HV) beneath iron borides zone have been determined. The microhardness gradient in borocarburized layer has been reduced in comparison with the only borided layer. An increase of distance from the surface is accompanied by a decrease of carbon content and microhardness in the carburized zone. The carbon and microhardness profiles of borided, carburized and borocarburized layers have been presented. A positive influence of composite layers (B + C) on the wear resistance was determined. The wear resistance of the borocarburized layer was determined to be greater in comparison with that for only borided or only carburized layers.

Microstructure and properties of composite (B + C) diffusion layers on low-carbon steel

Combined surface hardening with boron and carbon was used for medium-carbon 41Cr4 steel. The microstructure, carbon profiles and chosen properties of borided layers produced on the carburized 41Cr4 steel (similar in chemical composition as AISI 5140 steel) have been examined. This two-step treatment carburizing followed by boriding is termed borocarburizing. The microhardness profiles and wear resistance of these layers have been studied. In the microstructure of the borocarburized layer two zones have been observed: iron borides (FeB+Fe 2 B) and a carburized layer. The depth (100–125 μm) and microhardness (1450–1900 HV) of iron borides zone have been found. The carbon content (0.94–1.41 wt.%) and microhardness (950 HV) beneath iron borides zone have been determined. The microhardness gradient in borocarburized layer has been reduced in comparison with the only borided layer. The increase of distance from the surface is accompanied by the decrease of carbon content and microhardness in the carburized zone. The carbon and microhardness profiles of borided, carburized and borocarburized layers have been presented. A positive influence of borocarburizing on the wear resistance was determined. The wear resistance of the borocarburized layer was determined to be higher in comparison with that for borided or carburized layers.

A. Pertek

Papers

Microstructure and properties of borided 41Cr4 steel after laser surface modification with re-melting

Characterization of complex (B + C + N) diffusion layers formed on chromium and nickel-based low-carbon steel

The importance of carbon content beneath iron borides after boriding of chromium and nickel-based low-carbon steel

Microstructure and properties of composite (B + C) diffusion layers on low-carbon steel

Two-step treatment carburizing followed by boriding on medium-carbon steel