Latest ArticlesIn this paper, it is mainly analyzed and introduced the causes of internal hexagonal defect in super thick walled tube rolled with sizing mill in production of seamless steel pipe. Moreover, it is controlled by such means as increasing the rolling pass as well as reducing the reduction rate of each frame and coefficient of ovality so that the wall thickness accuracy of thick walled tube, ratio of first-grade products and yield of metal are improved.
This article starts with the product quality problem that the stand off between two sides of coupling is out of tolerance in production process of coupling thread processing. Moreover, it is introduced two process plans of coupling thread processing, lathe threading after boring of both sides and direct lathe threading after boring of single side. The times of chuck rolling-over can be reduced and the out-of-tolerance waste products of stand off for coupling and lathe threading caused by large axiality deviation of chuck can be avoided by direct lathe threading after boring of single side. It is mainly introduced the problem of stand off out of tolerance is solved with optimizing the coupling thread processing technology by technician and the effects are satisfactory.
In the paper, it is introduced the materials of coated tool and ceramic tool as well as matters needing attention in the process of using them, described the materials of two superhard material tools as well as summarized the development direction of cutter materials in our country.
In view of the shrinkage defect often appears in the process of casting V-type roll, the solidification process of casting shape for V-type roll is simulated with the casting process simulation software ProCAST. The area of casting defects is predicted and their causes are analyzed. As a result, the casting processes such as improving the pouring modes and riser of V-type roll are obtained so that the problem of shrinkage could be effectively solved and the casting process is optimized, which provide the effective guideline for production.
The tolerance rate of additional wall thickness for mandrel pipe mill is an important parameter to control the accuracy of wall thickness for steel pipe and main basis of selecting corresponding mandrel series for a pass. In the paper, the calculation formula for tolerance rate of additional wall thickness for three-roll mandrel pipe mill is derived as well as the additional tolerance values of reducing and increasing diameter of pass are simulated in pass detail and the simulated results are consistent with the calculated values. The result of variation for wall thickness calculated by this formula is basically the same as that calculated by external mathematical model.
In the paper, the research and development and application of non-standard oil casing in such four domestic large steel pipe production enterprises as China Baowu Steel Group, Tianjin Pipe Corp., Baotou Steel Group and Hengyang Pipe Group are introduced. With the increasingly harsh exploitation conditions in domestic oil and gas fields, its demand is increasing, while there are obvious differences between blocks and wells of oil and gas fields in China as well as a lot of work needs to be done further to evaluate its applicability, so the development direction of its research field is to formulate the unified standard and specification recognized by the industry on this basis.
The microstructure and properties of second generation on-line heat-treated U76CrRE rail with rare earth are stable through optimizing the smelting composition of billet and on-line heat treatment technology of rail during the process of its industrial trial production and research and development. The test results showed that its tensile strength could reach 1 280 MPa, elongation was greater than 10%, tread hardness (HBW) could reach 370~420 and there was no abnormal structure.
The high-temperature deformation behavior and continuous cooling phase transformation law for austenite of X80M steel are studied with thermal simulation compression and thermal expansion tests as well as the parameters of controlled rolling and controlled cooling are formulated and the industrial production is carried out. The study results showed that the deformation in final pass of controlled rolling and controlled cooling process was greater than 25% and it could be with perfect recrystallization, grain size was significantly refined and acicular ferrite + bainite with suitable proportion was obtained when the cooling rate was 20~25 ℃/s, the yield ratio of steel strip was about 0.86, impact energy at-20 ℃ was not lower than 370 J, shearing area of drop-weight test at-15 ℃ was not smaller than 95% as well as ductile-brittle transition temperature of Charpy V test was-45 ℃ to ensure the welded pipe to be with low bauschinger strength variation and ductile-brittle transition temperature and excellent resistance to buckling instability.
The Yangwan Iron Mine occurs in the hornblende plagioclase gneiss of the first formation complex of Wulashan Group of mesoarchean. The ore body is composed of magnetite quartzite and its form is simple, its discontinuous output is like bedded, lentoid in groups and bands as well as the occurrence is consistent with the stratum so that it is a direct indicator for deposit. The iron mine in this area is with stronger magnetism so that it can be an indirect indicator for deposit.
In this paper, it is expounded the acting force caused by ore transfer car on ore transporting highway and the destructional forms to pavement, analyzed the intensity composition characteristics of pavement of ore transporting highway with different grades of road materials and the economic benefits obtained after apply new gravel road materials in Bayan Obo Iron Mine through the comparative test of road material in the process of maintaining road.
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