Problems of the metallurgical quality of steel (nonmetallic inclusions)

Shtremel, M. A.

doi:10.1007/bf00694711

“…In the pipes from steel 35Ch the defect of structures was found -it is the inclusion of graphite in the structure of sorbite. In all parcels the defects were found in the form of non-metallic inclusions with admissible limit values (on GOST 1778) [8,9].…”

Section: Resultsmentioning

confidence: 99%

Quality assessment of structural steel in mining equipment manufacture

Korotkov

¹

,

Короткова

²

2017

MATEC Web Conf.

0

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Abstract. The relevance of this work is to form a methodical, scientific-based approach and the application of this experience in solving problems of quality control and improvement, as well as to identify ways of eliminating defects and small lifetime of the materials, used in critical parts and units of mining equipment. The aim of scientific research of the article is the study of discrepancy of structural steels quality problem, used for the manufacture of parts and components of mining equipment, established by standards. The goals are also, development and practical application of quality control methods in delivery condition and at all main stages of parts manufacture in accordance with the current state standards. As a result of steel quality complex control in delivery condition, it was possible to identify: the deviation of the chemical composition of steels and alloys, macrodefects, microdefects, deviation in hardness. Practical recommendations to eliminate and reduce and prevent the defects in parts and units used in mining engineering were developed. The paper presents practical experience in evaluation the quality of construction materials, which may be useful in design, manufacture and operation of mining industry and related manufacture industries.

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“…This method gives good results, but not worked in a factory practice and requires scarce powders of rare-earth metals. In the Company "Yurga Machine-Building Plant" is easier after taking the last sample of carbon in the liquid metal bucket to the processing of synthetic slag, this operation is well established in the metallurgical, chemical industries [11][12] and reduces the content of both elements.…”

Section: Discussionmentioning

confidence: 99%

Reasons for negative formation of structures in carbon steel processing of pressure

Valuev

¹

,

Данилов

²

2012

2012 7th International Forum on Strategic Technology (IFOST)

11

0

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Research using electronic microscope was carried out to study the structural and phase and deflected mode of material of hot-forged billets. It was revealed that the scalar density of dislocations in ferritic grains and in ferritic perlite layers of forging steel which cracked after manufacturing operations is one and a half time higher than in conditions material. Metal in this condition has higher content of sulfide of plate-type morphology. It has established that the reason of unwanted structural and phase condition is high carbon content, which lead to overheat of metal both in plastic working and final heat treatment.Keywords -perlite, globular modifications, optical metallography, structure, heat treatment. I. INTRODUCTIONThe most important physical factors determining the structural strength of steel products are: the type of defect substructure, morphology of the major components of the phase, morphology and crystal-chemical nature of the precipitates of secondary phases, the value of long-range internal stresses. They largely determine the susceptibility to cracking of blanks and finished products during hot forging [1].Comparative electron-microscopic study of the fine structure of steel St52.3N (an analog of the Russian steel 17 1 ) of the conditional (state I) and cracked after the manufacturing operations (state II), forging a transmission microscope -125K in the bright and dark field. Determined by the type of dislocation substructure in ferrite grains and ferrite interlayer of pearlite, the structure of pearlite colonies, shape, size, location and composition of particles of secondary phases, the level of long-range internal stresses.Preliminary analysis of the mechanical properties [2] showed that if the strength characteristics of both states are located on the same level, the state II is characterized by low plasticity. On fractures formed during the impact test, in this state, there are significant areas of brittle fracture. Standard metallographic studies revealed [2] that in both states steel is ferrite-pearlite aggregate. Perlite is presented as a plate and globular modifications. In both states the size as the ferrite grains, pearlite colonies and did not significantly differ. In the ferrite grains are observed separation of the secondary phases, and the pearlite colonies and at the interfaces -the pore size of 10 microns. Condition II has high porosity by 5-7% higher content of perlite and coarser structure of the latter.

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“…This method gives good results, but not worked in a factory practice and requires scarce powders of rare-earth metals. In the Company "Yurga Machine-Building Plant" is easier after taking the last sample of carbon in the liquid metal bucket to the processing of synthetic slag, this operation is well established in the metallurgical, chemical industries [11][12] and reduces the content of both elements.…”

Section: Discussionmentioning

confidence: 99%

Research into the Causes of the Cracking of Large Workpieces Low Carbon Steel by Pressure Treatment

Valuev

¹

,

Данилов

²

,

Serikbol

³

et al. 2014

AMR

5

0

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Research using electronic microscope was carried out to study the structural and phase and deflected mode of material of hot-forged billets. It was revealed that the scalar density of dislocations in ferritic grains and in ferritic perlite layers of forging steel which cracked after manufacturing operations is one and a half time higher than in conditions material. Metal in this condition has higher content of sulfide of plate-type morphology. It has established that the reason of unwanted structural and phase condition is high carbon content, which lead to overheat of metal both in plastic working and final heat treatment.

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Problems of the metallurgical quality of steel (nonmetallic inclusions)

Cited by 11 publications

References 4 publications

Quality assessment of structural steel in mining equipment manufacture

Quality assessment of structural steel in mining equipment manufacture

Reasons for negative formation of structures in carbon steel processing of pressure

Research into the Causes of the Cracking of Large Workpieces Low Carbon Steel by Pressure Treatment

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