Krzysztof Pańcikiewicz

Cracking of High-Strength Steel Welded Joints

ABSTRACT Fracture evaluation of welded joints in high-strength steels, with bainitic and martensitic structures, is presented and cracking mechanisms discussed. Hot cracks or microcracks formed during welding are further expanded as cold cracks on cooling. The cause of cracking is shown to be low temperature of weld solidification and deformation-induced contraction. Hydrogen can also be an important factor in this cracking.

Microstructure and Properties of a Repair Weld in a Nickel Based Superalloy Gas Turbine Component

Abstract The aim of the present study was to characterize the repair weld of serviced (aged) solid-solution Ni-Cr-Fe-Mo alloy: Hastelloy X. The repair welding of a gas turbine part was carried out using Gas Tungsten Arc Welding (GTAW), the same process as for new parts. Light microscopy, scanning electron microscopy, transmission electron microscopy, microhardness measurements were the techniques used to determine the post repair condition of the alloy. Compared to the solution state, an increased amount of M6C carbide was detected, but M23C6 carbides, sigma and mu phases were not. The aged condition corresponds to higher hardness, but without brittle regions that could initiate cracking.

Optimization of filler metals consumption in the production of welded steel structures

Abstract The paper presents the some aspects of the optimization of filler metals consumption in the production of welded steel structures. Correct choice of beveling method can allow to decrease cost of production and increase quality. The review of calculation methods of filler metal consumption at the design stage was carried out. Moreover, the practical examples of amount of filler metals calculation were presented and analyzed. The article also contain examples of mobile apps which are makes it easy to see welding costs in just a few seconds. Apps as well as simple excel spreadsheets with correct mathematic equations allows to optimize welding process.

TEM Investigations of the Microstructure of 7CrMoVTiB10-10 Steel Weld Metal

7CrMoVTiB10-10 (T24) steel is recommended for fabrication of boiler components such as water walls, water panels or headers without post weld heat treatment (PWHT). The chemical composition of this steel and cooling conditions after welding influence the susceptibility to cracking in weld metal during and after welding. TEM investigations showed that in the as-welded microstructure mixtures of bainite and martensite were dominating. This has an important implication for technological properties.