1. |
Paper, honoured with the Sir Charles Hatchett Award by the Institute of Metals, London: Developments in high speed tool steels |
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Archiv für das Eisenhüttenwesen,
Volume 58,
Issue 8,
2016,
Page 339-352
Robert Riedl,
Sadi Karagöz,
Hellmut Fischmeister,
Franz Jeglitsch,
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摘要:
This paper describes a research programme at the Austrian School of Mines (Montanuniversität) at Leoben, carried out since 1981 in cooperation with the Max‐Planck‐Institute for metals research in Stuttgart, on the fundamentals of alloy design for high speed tool steels. Among the results, the development of niobium‐alloyed grades has an important place. Controlled solidification studies with a gradient technique have clarified the influence of various alloying elements on the as‐cast microstructure of ledeburitic tool steels. A procedure for accurate quantitative metallography in SEM, combined with EDX and STEM‐EDX analysis of the chemical compositions of the carbide and matrix phases, has led to a quantitative model for the performance of high speed steels in metal cutting tools, in which the contributions of carbides and of the matrix are combined using empirically determined weight factors. An important role is played by the saturation of the matrix with vanadium and other carbide formers which are essential for secondary hardening. This saturation is related to the way in which these carbide formers are present in the annealed structure; this in turn is influenced decisively by the solidification path (via M6C or M2C) of the alloy. On the basis of these concepts, low alloyed, niobium‐containing economy grades have been developed whose performance is comparable to that of commercial high speed steels, and perspectives for the development of economic super high speed steels with niobium as an alloying element are indicated.
ISSN:0003-8962
DOI:10.1002/srin.198700230
出版商:Wiley
年代:2016
数据来源: WILEY
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2. |
Microstructure and toughness in high speed tool steels: the influence of hot reduction and austenitization temperature |
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Archiv für das Eisenhüttenwesen,
Volume 58,
Issue 8,
2016,
Page 353-361
Sadi Karagöz,
Hellmut Fischmeister,
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摘要:
Measurements of transverse rupture strength are reported for AISI M2, AISI M 35, AISI T 15 and ASP 30 produced by conventional ingot metallurgy, sintering of cold pressed powders, and hot rolling of HIP billets. Also reported are the size distributions of undissolved carbides and the effects of hot reduction and austenitization temperature on these and on the transverse rupture strength of test bars from the centre and the periphery of the bar stock, and of test bars oriented longitudinally and transversally to the rolling direction. Fracture initiating defects were identified and their size measured by SEM fractography. The results are discussed in terms of a fracture mechanical model for transverse rupture strength. It is inferred that in ingot‐derived materials, fracture is initiated by micro‐cracks formed by subcritical crack growth within the carbide stringers. In powder metallurgy materials, large carbides or carbide clusters initiate fracture. The model explains the dependence of transverse rupture strength on carbide distribution, degree of hot working, austenitization temperature, and specimen orientation. It is emphasized that transverse rupture strength is suitable for characterizing the defect population of a tool steel, but not the fracture resistance of small stressed volumes such as the cutting edge of a tool bit.
ISSN:0003-8962
DOI:10.1002/srin.198700231
出版商:Wiley
年代:2016
数据来源: WILEY
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3. |
Effects of molybdenum, phosphorus and microstructure on creep properties |
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Archiv für das Eisenhüttenwesen,
Volume 58,
Issue 8,
2016,
Page 362-368
Shingo Sato,
Hans Jürgen Grabke,
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摘要:
The effects of molybdenum, phosphorus and of microstructure on creep were studied at 550°C utilizing the model alloys Fe—3 Cr—0.05P, Fe—3 Cr—1 Mo—0.05P and Fe—3 Cr—1 Mo. The heat treatments were varied to obtain a ferritic or bainitic structure, the effect of a preheat treatment of 300 h at 550°C was investigated. Both Mo and P increase the creep strength by different mechanisms which lead to four types of creep curves, with 1 to 3 minima. The results are discussed using microstructural information from transmission electron‐microscopy.
ISSN:0003-8962
DOI:10.1002/srin.198700232
出版商:Wiley
年代:2016
数据来源: WILEY
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4. |
A review of the development and application of microalloyed medium carbon steels |
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Archiv für das Eisenhüttenwesen,
Volume 58,
Issue 8,
2016,
Page 369-376
Serosh Engineer,
Bernd Huchtemann,
Volker Schüler,
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摘要:
Microalloyed medium‐carbon steels with ferrite‐pearlite microstructure were developed in the FRG in early 1972, with the primary aim of saving the cost of heat treatment. A steel with roughly 0.47% C, 0.75% Mn, 0.060% S and 0.1 % V was first used for crankshafts in cars manufactured by one of the largest European automobile companies.The effect of microalloying elements such as vanadium and niobium (niobium instead of columbium is used in this paper) in these steels and their dependence on the cooling rate from drop‐forging temperatures is reviewed. Although niobium is more effective than vanadium, it leads to problems while manufacturing these steels with ~0.47% C, due to the high solution temperature of the niobium precipitates, so that preference has been given to vanadium. Further development work carried out to improve the ductility of these steels is reported. Steel compositions, which could make these steels applicable for various automobile and other engineering components, are presented.
ISSN:0003-8962
DOI:10.1002/srin.198700233
出版商:Wiley
年代:2016
数据来源: WILEY
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5. |
Contribution to the investigation of microsegregation processes in 13% Cr 4% Ni steel during long‐term annealing at 400°C |
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Archiv für das Eisenhüttenwesen,
Volume 58,
Issue 8,
2016,
Page 377-383
Jiřina Hubáčková,
Vladimír číhal,
Milan Koutník,
Adriena Potměšilová,
Karel Mazanec,
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摘要:
The present paper deals with the study of the development of microsegregation processes in the 13% Cr 4% Ni martensiteaustenite stainless steel during long‐term annealing. The long‐term annealing of 13% Cr 4% Ni steel at 400°C is accompanied by the decrease in notch impact toughness values, which is associated with an increasing tendency to the occurrence of the brittle failures. The conditions for the transition from the transcrystalline brittle failure to the intercrystalline brittle failure depend on the initial heat treatment affecting the achieved microstructure of investigated steel.The higher frequency occurrence of intercrystalline failure on the fracture surfaces of notch impact toughness specimens is accompanied by an enrichment of the prior austenite grain boundaries by phosphorus and nitrogen. At the same time the enrichment of intercrystalline fracture surfaces by nickel, or chromium was also observed. The application of an additional intercritical annealing after quenching accelerates the formation of intercrystalline failure towards shorter times during the isothermal annealing at 400°C.
ISSN:0003-8962
DOI:10.1002/srin.198700234
出版商:Wiley
年代:2016
数据来源: WILEY
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6. |
Mathematische Beschreibung der Σ‐∊‐Kurve des Zugversuches von gezogenem und angelassenem Automatenstahl 9 SMn 28 |
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Archiv für das Eisenhüttenwesen,
Volume 58,
Issue 8,
2016,
Page 384-388
Arnold Peiter,
Jürgen Jäckel,
Andreas Seger,
Michael Seger,
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摘要:
Die in vorangegangenen Untersuchungen erarbeiteten Meß‐ und Auswerteprogramme zur Beschreibung der Spannung‐Dehnung‐Kurven des Zugversuches werden auf den Automatenstahl 9 SMn 28 angewendet. Es zeigt sich auch hier, daß Hooke'sche‐Gerade, Fließhorizontale und Verfestigungsklothoide gut den ganzen Kurvenverlauf beschreiben. Der Klothoiden‐ParameterVändert sich nicht bei üblichen Prüfgeschwindigkeiten. Er steigt mit der Anlaßtemperatur. Seine Ungenauigkeit beträgt etwa ±0,5.
ISSN:0003-8962
DOI:10.1002/srin.198700235
出版商:Wiley
年代:2016
数据来源: WILEY
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