High-temperature tribological studies of plasma-nitrided tool steels

Abstract

During hot forging/forming operations, the die surface and near surface region is subjected to severe wear. The failure of dies originates from the surface region. In this research work, plasma nitriding was done on two hot forming tool steels namely AISI H11 and AISI H13. The aim is to develop a hard and wear resistance surface required for hot forming operations. The mechanical and microstructural properties of the developed nitrided layer were critically examined. Thereafter the tribological characteristics of the untreated and plasma-nitrided specimens were studied on high-temperature pin-on-disc tribometer under the constant load of 25 N, sliding speed 0.5 m s −1 , sliding distance of 1500 m at different temperatures ranging from room temperature to 600°C. The results showed that the main wear mechanisms is predominantly adhesive at room temperatures and 200°C and a combination of adhesive and abrasive at elevated temperatures (400°C and 600°C).

Directions of development and application of plasma nitriding in industry

“…Postupak nitriranja je alternativni metod površinskog ojačavanja za AISI H11 čelik koji može značajno poboljšati njegovu otpornost na habanje, otpornost na koroziju i zamor [107][108][109][110]. Prema [111] glavni mehanizam habanja nitriranih H11 i H13 čelika pretežno je bio adhezivni na sobnoj temperaturi i na 200[ºC] i kombinacija adhezivnog i abrazivnog na povišenim temperaturama (400 i 600[ºC]). [111] Figure 16.…”

“…Prema [111] glavni mehanizam habanja nitriranih H11 i H13 čelika pretežno je bio adhezivni na sobnoj temperaturi i na 200[ºC] i kombinacija adhezivnog i abrazivnog na povišenim temperaturama (400 i 600[ºC]). [111] Figure 16. [111] Slika 16 prikazuje dubinski profil mikrotvrdoće H13 i H11 PN uzoraka obrađenih na 500[ºC] za 24 sata korišćenjem 20[%] azota i 80[%] vodonika.…”

“…[111] Figure 16. [111] Slika 16 prikazuje dubinski profil mikrotvrdoće H13 i H11 PN uzoraka obrađenih na 500[ºC] za 24 sata korišćenjem 20[%] azota i 80[%] vodonika. Slika pokazuje da su površinske mikrotvrdoće uzoraka H11 i H13 bile 1089 HV 0,1 i 1045 HV 0,1 .…”

“…plazma nitriranih H11 i H13 čelika podvrgnutih ispitivanju habanja i trenja na različitim temperaturama [111] Figure 17. The average coefficient of friction of untreated and plasma-nitrided H11 and H13 steels subjected to wear and friction testing at different temperatures [111] Na slikama 18 i 19 prikazani su rezultati gubitka zapremine habanjem neobrađenih i obrađenih uzoraka H11 i H13 ispitivanih na različitim temperaturama. Maksimalni gubitak zapremine je zabeležen kod neobrađenih uzoraka pri ispitivanju na sobnoj temperaturi i 200[ºC].…”

Study on Upgradation in Carburizing Technologies for steel strength

“…In carburizing process, the Carbon monoixide (CO) gas is released by using charcoal as the medium and surface of the metals are carburized simultaneously. There has been further improvements are developed in the carburizing processes that have upgraded the steel strength significantly [1][2][3][4]. The steel carburizing is a thermo-chemical process that starts upon heat treatment of steel surface with the carbon.…”