6 results about "Lower yield" patented technology

This invention provides a high-strength steel with a low yield strength ratio of 1100MPa and its production method. The steel plate has the following chemical composition by mass percentage: C 0.15~0.17%, Si 0.58~0.6%, Mn 2.53~2.6%, Cr 0.53~0.8%, Ni 1.44~1.6%, Mo 0.2~0.6%, Nb 0.052~0.08%, V 0.02~0.08%, Ti 0.019~0.03%, Al 0.01~0.05%, Cu 0.83~1.5%, with the balance being Fe and unavoidable impurities. The steel plate has a yield strength ≥1100MPa, a yield strength ratio ≤0.88, an elongation ≥14%, and an impact energy ≥30J at -40℃. The finished steel plate has a thickness of 15mm and a microstructure of tempered lath martensite. The high-strength steel plate of this invention, with a yield strength ≥1100MPa, yield strength ratio ≤0.88, elongation ≥14%, and impact energy ≥30J at -40℃, exhibits a low yield-to-tensile ratio. The advantage of this invention lies in the fact that the salt bath Q&P heat treatment process achieves a good balance between high strength and a low yield-to-tensile ratio.

The application discloses a kind of low yield ratio high toughness 9Ni steel and its short process preparation method, belong to high-performance special steel manufacturing field.9Ni steel chemical composition is as follows according to percentage by mass: C:0.03~0.06%, Si:0.10~0.25%, Mn:0.50~0.80%, P≤0.003%, S≤0.001%, Ni:8.70~9.70%, Mo:0.08~0.15%, Ti:0.010~0.025%, Ca:0.0010~0.0030%, Alt:0.030~0.060%, N:0.003~0.006%, O≤0.0015%, the rest is Fe and inevitable impurity.Preparation method uses the short process technology of '' controlled rolling + online direct quenching + offline tempering'', and steel plate has high safety, high toughness and high quality, is suitable for LNG storage tank and other fields.

This invention relates to the field of high-toughness energy steel manufacturing technology, specifically to thin-gauge, low-yield-strength-ratio L245-L450 pipeline steel, its preparation method, and applications. The thin-gauge, low-yield-strength-ratio L245-L450 pipeline steel, by mass fraction, contains 0.04-0.08% C, 0.10-0.25% Si, 0.70-1.40% Mn, P≤0.015%, S≤0.010%, 0.010-0.035% Nb, 0.010-0.020% Ti, 0-0.20% Cr, 0.010-0.035% Als, N≤0.0060%, with the remainder being Fe and unavoidable impurities. This invention aims to provide microstructure control targets and suitable composition-processes for a series of pipeline steel products with low yield strength ratios (L245-L450). By optimizing the alloy element ratios and laminar flow cooling process parameters (e.g., controlling the average cooling rate of the water-cooled section to 10-20℃ with 3-8 sets of centrally opened front-end manifolds), a feasible standardized common technology is formed, which stably controls the yield strength ratio of the product within the range of 0.82-0.86. This meets the PSL2 grade performance requirements specified in the national standard "Hot-rolled wide steel strip for oil and gas transmission pipelines" while also possessing low carbon equivalent, excellent low-temperature toughness, and a wide process window, ensuring the comprehensive mechanical properties of the material.

This invention discloses a thin-gauge, low-yield, high-toughness 5Ni steel with the following chemical composition and mass percentages: C: 0.04–0.08%, Si: 0.15–0.25%, Mn: 0.30–0.60%, Ni: 4.75–4.95%, S≤0.005%, P≤0.008%, Alt: 0.020–0.050%, O≤20ppm, N≤40ppm, H≤2ppm, Cr+Cu+Mo≤0.30%, with the balance being Fe and impurities. The advantage of this invention is that it enables the steel to meet both low yield strength and high toughness requirements, while simultaneously ensuring excellent weldability and formability.

This invention discloses an isotropic bridge steel with low yield strength ratio and high toughness, and its manufacturing method. Its chemical composition by weight percentage is: C: 0.02–0.05%, Si: 0.25–0.45%, Mn: 1.00–1.40%, P≤0.01%, S≤0.003%, Nb: 0.02–0.05%, Ni: 0.40–0.70%, Cu: 0.25–0.45%, Mo: 0.10–0.20%, Cr: 0.50–0.80%, Ti: 0.005–0.02%, B: 0.001–0.0025%, Al: 0.01–0.04%, CEV: 0.36–0.52%, Pcm: 0.13–0.20%, I≥6.30, with the balance being iron and unavoidable impurities. The steel of this invention has excellent weather resistance and weldability, uniform overall plate performance, and minimal differences in transverse and longitudinal properties.