Heat Resistance of Steel N8G6M3FTB Obtained by Surfacing Cored Wire

The operational reliability of rolling production tools depends on the heat resistance of the steel from which they are made. To increase the performance of the rolls, a hardening surfacing with wear-resistant alloys is used. The effectiveness of the applied hardening technology depends on the functional characteristics of the deposited metal. The aim of the work is to study the tempering resistance in the state after heat treatment of the deposited steel (Fe-C-Ni-Mn-Mo-V-Ti-Nb system). It was established that the thermal resistance coefficient of steel 15N8G6M3FTB at temperatures from 650 to 800 °C varies from 0.76 to 0.66, which exceeds the heat resistance of steel 30Kh2V8F by 1.5 times. It is shown that in the fine structure of such a metal after tempering at 800 °C, large amounts of finely dispersed precipitates are observed. These precipitates have a rounded shape up to 100 nm in size and belong to the Laves phases - Fe2Mo, Fe2Nb, and Fe2Ti. The obtained high heat resistance values of 15N8G6M3FTB steel make it possible to recommend it for creating surfacing materials. Flux-cored wire based on this steel can be used for hardfacing hardening of tools operating at temperatures up to 800 °C inclusive.

Dilatometric and Microstructural Study of Martensite Tempering in 4% Mn Steel

This paper presents the results of martensite tempering resistance in 4% Mn steel. The material was quenched and tempered at 350 °C for 15, 30, and 60 min. The analysis of the quenching and tempering was carried out using dilatometric and microstructural approaches. The phase composition was assessed using X-ray diffraction. The Ms temperature and tempering progress were simulated using JMatPro software. The dilatometric analysis revealed a small decrease in the relative change in length (RCL) during tempering. This decrease was connected to the precipitation kinetics of cementite within the martensite laths. The microstructure investigation using a scanning electron microscope showed a very small amount of carbides, even for the longest tempering time. This showed the high tempering resistance of the martensite in medium-Mn steels. The hardness results showed an insignificant decrease in the hardness depending on the tempering time, which confirmed the high tempering resistance of martensite.

CRYODUR 2990

Cryodur 2990 is a good choice for cutting and shearing tools. The alloy is a cold work steel with hardness, good toughness, and high-tempering resistance combined with high-wear resistance. This datasheet provides information on composition, physical properties, and hardness. It also includes information on high temperature performance and wear resistance. Filing Code: TS-757. Producer or source: Schmolz + Bickenbach.

Effect of Heat Treatment on the Properties and Precipitations of High Strength Steel Plate for Construction Machinery

The effect of heat treatment on the microstructure and mechanical properties of High Strength steel plate Q960E for construction machinery was investigated. The result shows the quenching temperature have obvious effects on the mechanical properties, DQ can improve the toughness and the enchance tempering resistance, precipitations become more and bigger with the rise of the tempering temperature.

Thermodynamic Modelling of Carbide Precipitation in Hot Work Tool Steels with Different Silicon Contents

New grades have been developed in high alloy tool steels, enabling improved mechanical properties by modifications on Si, Cr or Mo contents. The correlation between alloy modifications and mechanical properties were successively correlated to microstructural aspects in previous work, especially in terms of secondary hardening carbides. In the present paper, thermodynamic and kinetic simulations were carried out and correlated to these data, especially in terms of Si effect on M3C carbide precipitation. Free energy evaluation points to easier formation of M7C3carbide in high Si steels, especially at high tempering temperatures, which are typical for hot work tool steels. Kinetic evaluations, based on the present simulations and literature, also show that cementite formation is retarded in high Si steels, which also lead to direct formation of M7C3. Regarding the low Si steels, cementite enrichment by Cr, Mo and V was also evaluated in terms of simulation. The results are in good agreement and help the explanation on the slower dissolution of cementite particles in low silicon steels, leading to important implications to the higher tempering resistance of these grades. Therefore, tempering simulation on the new hot work tool steel compositions aided the understanding of the microstructure modifications found experimentally.

Temper and Wear Resistance of Wide-Band Laser Cladded WC Coating

High power continuous wave (CW) CO2 laser cladding was performed on H13 steel, pre-coated by superfine WC. After laser cladding, the materials were tempered for 6 hours. Scanning electronic microscopy (SEM) was used to observe the morphologies of the cladding layer. X-ray diffraction (XRD) was employed to analyze the microstructure of the cladding layer. The changes of microhardness, temper resistance and wear resistance were tested. The microhardness of cladding layer before tempering was 1.4 times of that of base metal and 1.9 times after tempering at 500°C. The wear resistance and tempering resistance were improved.