Wyniki wyszukiwania - BazTech

1

Cracking of High-Strength Steel Welded Joints

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

Advances in Materials Science

|

2013

|

Vol. 13, nr 3(37)

76--85

EN

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.

2

Corrosion behaviour of plastically deformed high-Mn austenitic steels

Grajcar A., Krukiewicz W., Kołodziej S.

Journal of Achievements in Materials and Manufacturing Engineering

|

2010

|

Vol. 43, nr 1

228-235

EN

Purpose: The aim of the work was the comparison of corrosion resistance in an aqueous sulfuric acid solution of two high-manganese austenitic steels of the 0.05C-25Mn-Al-Si-Nb-Ti type in a plastically deformed state. Design/methodology/approach: Investigations were carried out on specimens obtained from a thermo-mechanically rolled sheet and then plastically deformed through bending and immersed in corrosive solutions (1N H2SO4) for 100 hours. The mass decrement was calculated by the gravimetric method, whereas the character of corrosion damages was observed in metallographic investigations using light and scanning electron microscopes both in the polished and etched states. Findings: It was found that after the thermo-mechanical processing one steel is characterized by an austenitic structure with numerous annealing twins, whereas in the second steel lamellar martensitic phases in an austenitic matrix occur. The investigations showed that the examined high-manganese steels have very low corrosion resistance in normal H2SO4. Higher impact on the corrosion resistance than the phase composition has the chemical composition. The mass decrement of the steel with martensite plates is a bit higher than that with a single-phase austenitic matrix. The specimens were intensively dissolved due to general corrosion accompanying by pitting and hydrogen cracking. Research limitations/implications: To investigate in more detail the corrosion behaviour of high-manganese austenitic steels, the polarization tests and the analysis of corrosion products should be carried out. Practical implications: The obtained results can be used for searching the appropriate way of improving the corrosion resistance of high-strength high-manganese austenitic steels. Originality/value: The corrosion resistance of two types of advanced high-manganese austenitic steels with different initial structures was compared. Hydrogen impact in austenitic steels was discussed. Keywords: Corrosion resistance; high-manganese steels; gravimetric method; pitting corrosion; general corrosion; hydrogen cracking

3

Hydrogen embrittlement and delayed failure

Szklarska-Śmiałowska Z.

Ochrona przed Korozją

|

2005

|

nr 9

290-294

EN

Examples of hydrogen embrittlement (HE) at high and low temperatures are given. The hydrogen induced cracking of Alloy 600 in a condition simulating that existing in a pressurized water reactor environment (350oC) and delayed fracture of an alloy at ambient temperatures are reported. The HE of bolts used in the automotive industry at ambient temperatures is discussed. In particular, a note has been taken to correlate the content of hydrogen in metals with their propensity to failure.

PL

Podano przykłady kruchości wodorowej w wysokich i niskich temperaturach. Opisano pękanie wodorowe stopu Alloy 600 w warunkach symulu- jących środowisko ciśnieniowego wodnego reaktora jądrowego (350oC), a także opóźnione pękanie tego stopu w temperaturze otoczenia. Omówiono kruchość wodorową stalowych śrub używanych w przemyśle motoryzacyjnym. Zwrócono uwagę na zależność między zawartością wodoru w metalach a ich skłonnością do pękania.