122results about How to "Reduce the ductile-brittle transition temperature" patented technology

The process of producing cold rolled high strength extra-deep drawing steel sheet in a bell type furnace includes the following steps: 1. smelting and casting steel billet with chemical composition comprising C not more than 0.006 wt%, Si not more than 0.30 wt%, Mn 0.15-1.40 wt%, P not more than 0.08 wt%, S not more than 0.02 wt%, N 0.001-0.005 wt%, Al 0.03-0.06 wt%, B 0.0003-0.002 wt%, Ti 0.005-0.015 wt%, Nb 0-0.03 wt%, and Fe and inevitable impurity for the rest; 2. heating to 1100-1250 and rolling; 3. cold rolling in the reduction rate over 73 %; 4. annealing inside a hydrogen or nitrogen-hydrogen bell type furnace at 690-730 deg.c and 5. leveling after annealing. The steel sheet has strength up to 390 MPa, high elongation and r value, high ability of resisting rework brittleness, and ductile-brittle transition temperature lower than -40 deg.c.

The invention discloses a process for improving rare-earth high-strength steel impact toughness. The process comprises the following steps of KR desulfurization slagging off, converter smelting, LF refining, RH refining and rare-earth treating, continuous casting, heating, rolling, accelerated cooling and heat treating. According to the process, aiming at the influence on the microstructure of low-alloy high-strength steel in the case that rare-earth exists, a research shows that rare-earth cerium Ce can improve the forms of inclusions and purify grain boundaries, so that the strength of the grain boundaries is improved, the possibility that cracks extend due to the through defects is reduced, and the impact toughness is improved; and addition, the impact toughness can be improved throughrefining austenite grain boundaries, and meanwhile, adding the rare-earth cerium Ce can enable the ductile-brittle transition temperature of the steel to reduce by about 10 DEG C.

The invention relates to steel suitable for a drill rod joint in a low-temperature environment and a heat treatment process of the steel. The steel used for a drill rod joint comprises the following components by weight percent: C 0.25-0.35%, Mn 0.50-1.00%, P<=0.015%, S<=0.008%, Mo 0.15-1.00%, Ni 0.75-1.50%, Cr 0.80-1.50%, two or more of Si<=0.30%, Al<=0.03%, V<=0.10%, Ti<=0.03% and Re<=0.005%, and the balance of Fe and inevitable trace elements. The heat treatment process of the steel suitable for a drill rod joint is as follows: heating the steel in a furnace to 900-960 DEG C; carrying out heat insulation for 1.0-1.5 hours; putting the steel into a quenching medium and cooling down completely; tempering at the temperature of 660-690 DEG C; carrying out heat insulation for about 2.0-2.5 hours; and then taking the steel out of the furnace. After the steel is treated according to the process, when the yield strength of the steel is 905MPa, longitudinal and full-size charpy impact power average value at -60 DEG C is 110J, the fracture fiber rate is 100% on the average, and the ductile-brittle transition temperature is -85 DEG C.

The invention belongs to the technical field of steel material production, and particularly relates to a 355MPa thick steel plate with low-temperature toughness and a preparation method thereof. The 355MPa thick steel plate with the low-temperature toughness is composed of the following components according weight percent: 0.04 to 0.14% of C, 0.2 to 0.5% of Si, 1.0 to 1.6% of Mn, less than 0.018% of P, less than 0.005% of S, 0.015 to 0.045% of Nb, 0.02 to 0.05% of V, 0.008 to 0.020% of Ti, and the balance of Fe and inevitable impurities. The thick steel plate has good low-temperature (-60 DEG C) impact toughness, and additionally, high strength, high toughness and good welding performance of the thick steel plate are achieved in the condition of the low-carbon content by adopting the preparation method.

The invention relates to a high-phosphorous weather-proof steel cast-rolling thin strip with negative phosphorous segregation on the surface and a preparation method thereof. The chemical components of the thin strip in terms of percentage by mass are as follows: 0.061-0.099% of C, 0.15-0.75% of SiO, 0.20-0.49% of Mn, 0.07-0.30% of P, 0.02% or less of S, 0.25-0.50% of Cu, 0.30-1.25% of Cr, 0.12-0.65% of NiO, and Fe as remainder. The preparation method of the thin strip comprises the following steps of: melting, refining, casting and rolling the refining liquid steel by a double-roller thin strip casting and rolling device, and controlling the cast-on temperature at 1540-1600 DEG C and the casting and rolling speed at 12-60m/min, and presetting the roll-gap as 1-4mm; obtaining the cast-rolling strip with negative phosphorous segregation on the surface, with a thickness of 1-5mm; and then cold-rolling and annealing. The negative phosphorous segregation on the surface guarantees the strength and the plasticity of the thin strip and also greatly improves the anti-corrosion performance of the thin strip; the ductile-to-brittle transition temperature of the high-phosphorous weather-proofsteel cast-rolling thin strip with negative phosphorous segregation on the surface is about 10 DEG C lower than that of the products produced by common processes, and the tenacity of steel is improved.

The invention discloses a W-Mo-Re-HfC alloy material. The W-Mo-Re-HfC alloy material is prepared from the following raw materials by weight: 10% to 30% of molybdenum, 1% to 25% of rhenium, 0.2% to 10%of hafnium carbonate and the balances tungsten and inevitable impurities. The invention further provides a preparation method of the W-Mo-Re-HfC alloy material. The preparation method comprises the following steps of: (I) carrying out ball milling and uniformly mixing molybdenum powder, rhenium powder, hafnium carbonate powder and tungsten powder; and carrying out crushing and sieving after hydrogen reduction to obtain mixed powder; and (II) sintering the mixed powder in a vacuum hot-press sintering furnace, and then cooling the mixed powder with the furnace to obtain the W-Mo-Re-HfC alloy material. The preparation method of the W-Mo-Re-HfC alloy material disclosed by the invention is simple in a technological process; the prepared alloy material is low in oxygen content; the microstructure is uniform; a base body consists of W, Mo and Re solid solution phases; good plasticity is realized; submicron and nanometer HfC phases are uniformly distributed in the base body so that the alloymaterial is excellent in plasticity and also has good room-temperature and high-temperature strength.

The invention relates to precipitation strengthened heat resistant steel and a preparation process of the precipitation strengthened heat resistant steel. The components of an alloy meet the followingrange requirements by mass percent: 003-0.06% of C, 6-10% of Ni, 8-13% of Cr, 1.5-2.4% of Al, less than or equal to 3% of Co, less than or equal to 0.1% of Nb, less than or equal to 0.1% of Zr, and the balance of Fe; the prepared alloy is smelted into an alloy mother liquid and is finally prepared into an alloy ingot; the alloy ingot is rolled into a sheet at the temperature range of 850-1100 DEGC; and the rolled sheet is subjected to solid solution treatment and aging treatment to obtain the precipitation strengthened heat resistant steel. The heat resistant steel is excellent in room temperature toughness and has an excellent strength property at the same time. The room temperature tensile strength of the alloy is not lower than 1000 MPa, the yield strength exceeds 900 MPa, the room temperature elongation percentage is higher than 12%, and the reduction of area is higher than 50%.

The invention discloses 690 MPa grade high-strength low-yield-ratio medium-manganese steel medium-thickness steel and a manufacturing method, and relates to the technical field of steel smelting. Thesteel comprises the following chemical components of, in percentage by mass, 0.05%-0.10% of C, 4.1%-4.7% of Mn, 0.15%-0.4% of Si, less than or equal to 0.010% of P, less than or equal to 0.003% of S,0.01%-0.05% of Ti, less than or equal to 0.6% of Ni + Cr + Mo, and the balance Fe and inevitable impurities. The requirements of ultra-high strength steel safety performance and construction cost in acomplex environment in the field of engineering machinery can be met.

The invention discloses a corrosion-resistant metal coating used for the outer surface of a gear box. The corrosion-resistant metal coating comprises, by mass, 0.06%-0.08% of C, 0.15%-0.18% of Mn, 10.76%-10.79% of Cr, 2.12%-2.15% of Ni, 0.13%-0.15% of Mg, 0.21%-0.23% of Mo, 0.25%-0.27% of Co, 0.06%-0.08% of V, 0.42%-0.44% of Ti, 0.22%-0.25% of Na, 0.17%-0.19% of Ga, 0.22%-0.25% of Ce, 0.16%-0.18% of Nd, 0.32%-0.38% of La and the balance Fe.

The invention discloses a steel plate with excellent low-temperature toughness. The steel plate comprises the following chemical elements in percentage by mass: 0.02-0.15% of C; 0.10% to 0.5% of Si; 0.30% to 1.60% of Mn; 0.10% to 1.00% of Cr; 0.30% to 1.00% of Ni; 0.005% to 0.10% of Ti; 0-0.60% of Mo; 0.10% to 0.80% of Cu; 0.01% to 0.06% of Al; 0.003-0.06% of Nb, 0-0.08% of V, and 0 < N < = 0.035%; and the balance of Fe and other inevitable impurities. In addition, the invention also discloses a manufacturing method of the steel plate with excellent low-temperature toughness, which comprises the following steps: (1) smelting and casting; (2) heating; (3) rolling; and (4) cooling.

The invention relates to automotive axle housing steel. The automotive axle housing steel comprises the following components in percentage by weight: 0.06-0.10% of C, 0.20-0.40% of Si, 1.30-1.50% of Mn, less than or equal to 0.025% of P, less than or equal to 0.008% of S, 0.020-0.040% of Als, 0.010-0.015% of Nb, 0.050-0.080% of Ti and the balance of Fe and unavoidable impurities. The invention also relates to a preparation method of the automotive axle housing steel. The preparation method comprises the following steps of converter smelting, LF refining, casting, roughing and finishing. By adding less alloying elements Ti and Nb and controlling the content of N and controlled rolling and cooling process, 600MPa-grade steel is obtained and has excellent mechanical properties and formability.

The invention relates to a high-hardenability and high-strength ultra-thick marine steel plate. The high-hardenability and high-strength ultra-thick marine steel plate is 60-150 mm thick and is composed of the chemical components of, by weight percentage, 0.04-0.08% of C, 4-9% of Mn, 0.10-0.25% of Si, 0.01-0.03% of Als, 0.2-0.5% of Mo, 0.025-0.050% of Nb, less than or equal to 0.04% of S, less than or equal to 0.007% of P, and Fe and impurity elements as balance. The high-hardenability and high-strength ultra-thick marine steel plate can solve the phenomenon of non-uniformity of thickness direction texture and performance, expand the thickness specification to 150 mm with low-temperature toughness still meeting the operating requirements at -80 DEG C and obtain low yield ratio under equal yield strength conditions, specifically, the parts of 1/4 and 1/2 thickness of the steel plate reach a yield strength not lower than 690 MPa, a yield ratio not higher than 0.86, an elongation percentage not lower than 20%, and a -80 DEG C low-temperature impact energy greater than 100 J.

The invention belongs to the technical field of fourth-generation lead bismuth cooling fast reactor structural materials, and particularly relates to a ferrite martensite steel ladle shell material and a preparation method thereof. The ferrite martensite steel ladle shell material comprises the components of 0.08wt%-0.16wt% of C, 0.30wt%- 0.8wt% of Mn, 0.50wt%-1.20wt% of Si, 8.5wt%-10.5wt% of Cr, 1.0wt%-2.5wt% of W, 0.10wt%-0.40wt% of V, 0.10wt%-0.40wt% of Ta, 0.005wt%-0.08wt% of Zr, 0.005wt%-0.05wt% of La, 0.008wt%-0.04wt% of N, and the balance Fe and impurities. The preparation method of the ferrite martensite steel ladle shell material comprises the following process steps of (1) smelting; (2) casting; (3) forging; (4) extruding; (5) pipe blank machining and heat treatment; (6) multi-pass cold rolling and intermediate heat treatment of the alloy; and (7) final heat treatment of the pipe. According to the ferrite martensite steel ladle shell material and the preparation method thereof, through the innovative component design, the optimized pipe machining deformation process and the heat treatment technology, the microstructure of the material is improved, grains are refined, and therefore the comprehensive performance of the alloy is improved.

The invention discloses low-nickel type medium-chromium ferrite stainless steel and a manufacturing method thereof. The low-nickel type medium-chromium ferrite stainless steel comprises, by weight, 0.7%-1.2% of Ni, 0.002%-0.012% of C, 0.002%-0.020% of N, 0.10%-0.50% of Si, 0.1%-0.50% of Mn, 17.00%-22.50% of Cr, 1.70%-2.50% of Mo, 0.15%-0.45% of Nb, 0.05%-0.25% of Ti, 0.005%-0.010% of O, and the balance Fe and inevitable impurities. The following relational expressions are met, wherein (C+N) is smaller than or equal than 0.030%, Nb/Ti is equal to 1.5-4, and (Nb+Ti)/(C+N) is equal to 12-22. The low-nickel type medium-chromium ferrite stainless steel obtained through the method has excellent low-temperature toughness and high strength; the ductile-brittle transition temperature is smaller than or equal to -40 DEG C, the yield strength is larger than or equal to 330MPa, and strength of extension is larger than or equal to 445MPa; and the metallographic structure is a pure ferrite equiaxed grain structure.

The invention discloses a tungsten-zirconium carbide-rhenium alloy and a preparation method thereof. The alloy mainly comprises metal tungsten, wherein the alloy also includes 0.2wt percent to 1.0wt percent of zirconium carbide, and 0.5wt percent to 3.0wt percent of rhenium. The preparation method comprises the following steps of putting metal tungsten powder, zirconium carbide powder and rhenium powder in a protective atmosphere or a vacuum or alcohol in proportion to be mixed uniformly for obtaining mixed powder, first putting the mixed powder under pressure of 200MPa to 600MPa to press for obtaining a green compact, afterwards, putting the green compact in the protective atmosphere or the vacuum, and sintering and molding the green compact at a temperature of 1500 DEG C to 2200 DEG C to prepare a target product. The tungsten-zirconium carbide-rhenium alloy prepared by the invention has excellent performances of higher high-temperature strength and plasticity and a high recrystallization temperature.

The invention relates to the field of vacuum induction smelting, particularly an ultrapure smelting technical method of low-alloy high-strength steel. A CaO refractory material is utilized to form a crucible, and a vacuum induction smelting method is utilized to acquire the ultrapure low-alloy high-strength steel. In the melting period, carbon in the alloy raw material is utilized to carry out primary stage deoxidization and denitrification; in the refining period, the refining temperature is enhanced to reinforce the thermodynamicical and dynamic conditions for deoxidization and desulfurization, and effective deoxidization and desulfurization are carried out on the crucible wall part and the molten steel surface; and in the deoxidization and desulfurization period, strong deoxidizer and desulfurizer are added to carry out end deoxidization and desulfurization on the alloy so as to further lower the oxygen and sulfur contents in the alloy, so that the oxygen content is controlled below 10ppm, the sulfur content is controlled below 30ppm, and the nitrogen content is controlled below 30ppm. The invention can effectively improve the low-temperature impact toughness of the low-alloy high-strength steel, and further lower the tough-brittle transition temperature, thereby widening the application range of the low-alloy high-strength steel, enhancing the hot working properties of thealloy and acquiring the high-quality low-alloy high-strength steel.