Abstract The aim of this work is to study the effect zirconium and niobium on refinement grain size mechanical properties micro-alloyed cast steels in heat treated conditions. Five with different compositions, as steel without microalloying elements (i) 0.05% Zirconium (Zr), (ii) (Zr) Niobium (Nb), (iii) 0.10% (iv) (Nb) were investigated. samples are normalized at 1000 °C followed by air coolin...

The article reflects the results of many years’ (since 1972) research of structural, hydrodynamic, thermophysical and mechanical properties of metal felt capillary structures (MFCS) of heat pipes (HP). These structures were made from the discrete copper, stainless steel, or nickel sintered fibres of 0.002 to 0.01-m length and diameter within 20 to 70 μm. They were intended for the HP with shell...

grate bar is an industrial part which is used in the indurating furnace of an iron ore pelletizing plant. steel part ofthe grate bars are expected to have high resistance to atmospheric oxidation because of its contact with hot gases(up to 920 °c) during the normal operation of the process. in this study, different samples from several sections ofused grate bars with apparent defects were selec...

This study presents a failure analysis in two reformer tubes used for hydrogen production petrochemical industry. These (Tube A and Tube B) were made by the centrifugal casting of HP-Nb alloy such way that one contained titanium as micro-element, other was free from its chemical composition. Although subjected to similar creep conditions, failed after only 46,000 h operation against design life...

Titanium additions are often used for boron factor and primary austenite grain size control in high- ultra-high-strength alloys. Due to the risk of formation coarse TiN during solidification addition titanium is limited respect nitrogen. The nitrides working as non-metallic inclusions formed last front can degrade fatigue properties weldability final product. In presented study three microalloy...

The heat-resistant steel after aluminized was treated by laser shock processing (LSP) with high power Nd:YAG laser, and then was tensile tested at 400 . The effects of the high °C -temperature behavior after LSP were analyzed from residual stress and fracture organization. The results showed that the yield strength and tensile strength of heat-resistant steel after aluminized were improved obvi...