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It has recently been suggested that the size effect and the enriched Mn concentration of ultrafine austenite grains are the two main contributors to austenite stability. We argue here that the chemical composition of austenite, particularly the C content, and the hydrostatic pressure on the transforming austenite grains are the intrinsic factors that affect the stability, rather than the austenite grain size. © 2012 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Shi Z.-Z.,Control Iron and Steel Research Institute, China
Journal of Alloys and Compounds | Year: 2013

Lath-shaped β-Mg2Sn precipitates with (near) Burgers OR in α-Mg matrix are found to be enclosed by three to four pairs of facets. The habit plane (HP) is (1 1 0)β//(0 0 0 1)α, while the major side facet (MSF) is (-1 1 1)β or 0.36° from (1 2 -3 0)α, the trace of which is about 10° from [1 -1 0 0]α. The minor side facet with a higher frequency of appearance is (1 -1 1)β//(-2 1 1 0)α, while that with a lower frequency of appearance is (1 -1 0 0)α or 0.50° from (-1 1 -3)β. Based on geometrical models, the MSF is proposed to obey a Δg parallelism rule, which requires a rotation of -0.15° from the exact Burgers OR. The calculated OR and morphology agree well with the observed ones. © 2013 Elsevier B.V. All rights reserved.

Cheng Y.,Control Iron and Steel Research Institute, China
Procedia Engineering | Year: 2011

In order to solve the current lack of detection method of impurity elements in the vanadium-aluminum alloy, this paper established by inductively coupled plasma atomic emission spectrometry (ICP-AES) direct simultaneous determination of 15 kind of micro or trace impurity elements, including boron, tungsten, silicon, iron, lead, tin, arsenic, nickel, chromium, cobalt, copper, phosphorus, manganese, magnesium, molybdenum. Vanadium-aluminum alloy sample was digested as the solution with hydrochloric acid and nitric acid, and then by nebulizer spray aerosol was introduced in the plasma torch, the elements in the 8000-10000K high temperature was excited and emission of characteristic lines, by detecting the signal intensity of the characteristic lines for quantitative analysis. Method detailed study between the sample substrate the vanadium and aluminum as well as the co-existing elements disturbing effect, and through the optimal analysis spectral line and the background adjusted the position to avoid the spectrum disturbance. Selects the method which the substrate match and the synchronized background adjust unify to eliminate highly concentrated the vanadium aluminum base body to the test solution atomization, transmission, ICP balanced and the stimulation and the element determination each kind of disturbing effect factor, and optimize the operation control parameters of the spectrometer. In this law determination aerospace rank's vanadium-aluminium alloy impurity element's result indicated: detection limit 5.0 ∼ 100μg / L, the background equivalent concentration of 5-95μg / L; recovery rate of 95.3% to 110.0%; in content ≥0.010% RSD≥4.88%; between 0.001% and 0.010% content scope RSD≤8.89%. The actual sample results were the same as the Germany GfE company which is the world-class manufacturer of the vanadium-aluminium alloy, and detection elements and scope over the Gfe. Method measured the European standard samples of the vanadium-iron alloy consistent with the standard value, whose matrix composition similar to the vanadium-aluminium alloy. © 2011 Published by Elsevier Ltd.

Dong H.,Control Iron and Steel Research Institute, China
Science China Technological Sciences | Year: 2012

In order to meet the progressive requirement for the performance improvement of steel, the author proposed a novel microstructure featured with multi-phase, meta-stable and multi-scale (so-called as M3). And then, the new technologies could be developed to process three prototype steels with high performance: the third generation high strength low alloy (HSLA) steels with improved toughness and/or ductility (AKV(-40°C)≥200 J and/or A≥20% when Rp0.2 in 800-1000 MPa), the third generation advanced high strength steels (AHSS) (Rm×A≥30 GPa% when Rm from 1000 MPa to 1500 MPa) for automobiles with improved ductility and low cost, and heat resistant martensitic steels with improved creep strength (σ10000650≥90 MPa). It can be expected that the new technology developed will remarkably improve the safety and reliability of steel products in service for infrastructures, automobiles and fossil power station in the future. © 2012 Science China Press and Springer-Verlag Berlin Heidelberg.

Control Iron and Steel Research Institute, China | Date: 2015-03-13

The invention relates to metal solidification and continuous casting, in particular to a back-up roll device and method for conducting corner deformation on a chamfered continuous casting slab. The back-up roll device comprises back-up rolls with -angle bevels, movable bearing seats, bearing seat moving rails, bearing seat motion holding mechanisms and inner arc or outer arc frames of a casting machine. The back-up rolls are arranged on the inner and/or outer arc frames of the horizontal segment of the casting machine. Support surfaces of the back-up rolls make contact with and squeeze smaller obtuse angles adjacent to the wide face of the inner or outer arc on the chamfered continuous casting slab, and therefore each smaller obtuse angle is squeezed into two larger obtuse angles. The back-up roll device and method for conducting corner deformation on the chamfered casting slab can achieve the purposes of eliminating edge slivers.

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