Ömer Faruk Murathan

Ankara University · Sincan 1. OSB MYO

This research investigates the improvement of impact toughness by changing isothermal heat treatment time for an alloy having high boron/chromium constituents. Different boron contents (0.5–5.00 wt% B) were added into high chromium steel by sand casting. Along with JMatPro program, dilatometry used to calculate critical temperatures and transformat...

In this work, the change on the microstructure and mechanical properties of high chromium steel investigated by adding ultra-high boron contents. Specimens produced by casting method. A total of 430 type martensitic stainless steel scraps melted in an induction furnace where the chemical composition of melt controlled (by adding ferro alloys, de-ox...

The effect of isothermal heat treatment temperatures under martensite start (M s ) temperature on the microstructure and mechanical properties of high-silicon commercial spring steel has been investigated. For this purpose, tensile specimens are prepared from AISI 9254 steel isothermally heat-treated under M s temperatures (225 °C, 250 °C, and 275...

It is well known that industrial wastes are considerably hazardous to the environment therefore recycling wastes by merging them into the building materials is an appropriate solution. This research reviews usability of waste casting sand (WCS) and waste boron (WB) in clay based bricks. For this purpose, composite bricks produced by adding appropri...

In this study, the effect of austenitizing temperatures and low-temperature isothermal heat treatment (below martensite start temperature) on the microstructure and mechanical properties of AISI 9254 high silicon spring steel has been investigated. Experimental studies show that ultra-fine carbide-free bainite, tempered martensite and carbon enrich...

In this study, multiwalled boron nitride microtubes (BNMTs) were synthesised from amorphous boron powder in pure nitrogen atmosphere controlled graphite furnace at 1300°C for 6 h with amorphous boron/manganese (IV) oxide (MnO2) catalyst mass ratio of 1/1. It was found that the synthesised BNMTs outer diameters and the lengths vary between 0.68 and...

In this study, boron nitride (BN) was produced by chemical vapor deposition (CVD) method on silicon carbide (SiC) powders at low temperatures. In order to obtain BN, urea (CO(NH2)2) and boric acid (H3BO3) were used as starting materials and different boric acid/urea ratios (1/1 and 1/3) were studied. After getting homogenous mixture of boric acid a...

Boron nitride is an artificial material with superior properties such as high thermal shock resistance, thermal conductivity, electrical insulation, chemical stability and lubrication. Due to its superior properties, it is used in chemistry and metallurgy industries, high temperature applications, electronics and electrotechnical industry, refracto...

Tool steels are a special group of ferrous alloys that are used in severe applications, but also demand highest quality in every processing step. Typical microstructure of those alloys are composed of evenly dispersed alloy carbides in a matrix of tempered martensite. Controlling the formation of desired structure, specifically after the final hard...

Present study focuses on, development of fine carbide free bainite + martensite structure in AISI 9254 commercial high silicon spring steel by low temperature isothermal heat treatment. For this aim, tensile specimens were austenitized at 1020°C for 30 min and then isothermally heat treated for 168 hours (1 week) in a molten salt bath at 225°C whic...

In the present study, effect of tempering temperatures on microstructure and mechanical properties of AISI 9254 spring steel has been investigated. For this purpose, tensile specimens austenitized at 870°C for 30 min and then oil quenched at 80ºC. After quenching, specimens tempered at four different temperatures (250°C, 350°C, 450°C and 550°C) for...

Hexagonal boron nitride (h-BN) is used in high temperature bed solid lubricants, glass and metal of the casting mold and the mold release, because of high temperature refractiveness, thermal conductivity, chemical inertness and easy processability properties. In this study, XRD and SEM analysis of high purity h-BN were done for characterization stu...

Heat treatment operations of steels usually start with austenitization. The properties of the heat treated products, therefore, are strongly influenced by the prior austenite grain structure. The present study aims at investigating the possibility of using magnetic Barkhausen noise (MBN) technique to evaluate the prior austenitic grain structure. F...

In this study, effect of austempering heat treatments on microstructure and mechanical properties of AISI 9254 commercial spring steel has been investigated. For this aim, tensile specimens were austenitized at 870 °C for 30 min. and then austempered at 300 °C and 400 °C in molten salt bath for 30 min. Microstructures of the specimens were characte...