Search Results

You are looking at 1 - 5 of 5 items for

  • Author: K. Pańcikiewicz x
Clear All Modify Search
Open access

K. Pańcikiewicz

Abstract

Gas Tungsten Arc butt welded joints of tubes of 7CrMoVTiB10-10 made using bainitic-martensitic P 24-IG filler metal were found to be susceptible to root cracking. This was avoided by using the CMS-IG filler metal and austenitic EPRI P87 filler metal. Detailed coefficient of thermal expansion analysis for both filler metals was performed. Unfortunately, CMS-IG filler metal is characterized by a lower creep rupture strength than P 24-IG. For this reason, the joints were produced by the 141 method with using two filler metals: P 24- IG and EPRI P87. All the welded joints was characterized by the B quality level. Macrostructural, microstructural and hardness data for both welded joints are presented. The standard requirement, < 350 HV10, was marginally not met and was achieved through post weld heat treatment.

Open access

E. Lichańska, P. Kulecki and K. Pańcikiewicz

Abstract

The aim of the study was to evaluate the effect of chemical composition on the structure and mechanical properties of Mn-Ni-Mo and Ni-Mo-Cu PM steels. Pre-alloyed powder Astaloy 85Mo, diffusion alloyed powders Distaloy AQ and Distaloy AB produced by Höganäs, low carbon ferromanganese, carbonyl nickel powder T255 with three-dimensional filamentary structure and graphite CU-F have been used as the basic powders. Three mixtures with compositions of Fe-1%Mn-(0.5/1.75)%Ni-(0.5/0.85)%Mo-0.8%C and Fe-1.75%Ni-0.5%Mo-1.5%Cu-0.8%C were prepared in a Turbula mixer. Green compacts were single pressed in a steel die at 660 MPa according to PN-EN ISO 2740 standard. Sinterhardening was carried out at 1250°C in a mixture of 95% N2+5% H2 for 60 minutes. Mechanical tests (tensile, bend, hardness) and microstructural investigations were performed. Additionally, XRD and EDS analysis, fractographic investigations were carried out. The microstructures of steels investigated were mainly bainitic or bainitic-martensitic. Addition 1% Mn to Distaloy AQ based steel caused increase of tensile properties (YS from 422 to 489 MPa, UTS from 522 to 638 MPa, TRS from 901 to 1096 MPa) and decrease of plasticity (elongation from 3.65 to 2.84%).

Open access

K. Pańcikiewicz, L. Tuz, Z. Żurek and Ł. Rakoczy

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.

Open access

K. Pańcikiewicz, A. Zielińska-Lipiec and E. Tasak

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.

Open access

Ł. Rakoczy, M. Grudzień, L. Tuz, K. Pańcikiewicz and A. Zielińska-Lipiec

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.