Characterization of Adherence Steels Hardened Superficially

Abstract

This study evaluates the behavior of the adherence layers -sawn flat iron boride formed on the surface of steels used in manufacturing industry in Mexico. In steels AISI 1018, AISI 8620 and AISI 316 was characterized this behavior, boriding thermochemical treatment with box technique, with a processing temperature of 1273 °K, with an exposure time of 8 hours. Furthermore the adherence is assessed by the Rockwell C hardness technique prescribed by the German standard VDI 3198 of traction, this impact test qualitatively determine the type of adherence formed three thermochemical steels treated by the technique of boriding. Moreover optical microscopy determines the type of film morphology FeB/ Fe 2 B of each of the materials exposed to a boriding, also shows the thicknesses of the phases generated in the surface type in all three steels boriding. Phase presence boride FeB/Fe 2 B was determined by X -ray diffraction (XRD). Technique for scanning electron microscopy (EDS) was evaluated qualitatively the presence of FeB/Fe 2 B of boronizing. Otherwise determines the hardness and elastic modulus by nanoindentation technique of the phases present in the three steels. Lastly, AISI 1018 and AISI 8620 are bounding scale H1 to H3, the AISI 316 steel has an adherence of H3 to H6 under German standard VDI 3198.

Characterization and Fracture Toughness on AISI 8620 with Hard Coatings

“…where CI K is the fracture toughness, ( P ) is the indentation load, ( g ) is the crack length generated on corners of the indentation, ( l ) is the half of the diagonal length of the indenter, crack length measured from the center of the tread indenter ( C ) , ( E ) is the elastic modulus on iron boride phase on AISI 8620 is 292.25±2.75 GPa obtained in [5], ( H ) is the hardness of the material and H .…”

“…The quality of the hard coatings obtained on AISI 8620 surface is effective in the treatment conditions, to a temperature of 1223 K with times of 6 to 8 h, as they have the acceptable quality of adhesion (HF4) while for the condition of 1273 K with the times of 6 to 8 h, have the quality of insufficient adhesion (HF5) due to the presence of CrB, MnB in the borided layer. The work done by N. Lopez et al [12] and D. Sanchez et al [5] obtained as a result on AISI 8620 steels borided through powder pack boride process, their results show the presence of FeB and Fe 2 B phases and in condition of 1273 K have optimal adhesion (HF1-HF4) but Taktak et al [13] found that their adhesion decreased with an increase of boriding time and temperature on H13 and AISI 304 steels boriding.…”