9 results about "Bake hardening" patented technology

This invention relates to the field of aluminum alloy materials technology, specifically to a low-zinc-content 6-series aluminum alloy sheet and its manufacturing method. The components and their weight percentages in the low-zinc-content 6-series aluminum alloy sheet are as follows: Si content 0.90-1.20%, Mg content 0.45-0.65%, Cu content 0.12-0.20%, Zn content 0.05-0.10%, Fe content ≤0.28%, Mn content 0.02-0.20%, Cr content ≤0.10%, Ti content ≤0.15%, containing at least one of In, Cd, La, and Ce, and the total content of In, Cd, La, and Ce is 0.01-0.10%; the content of a single impurity ≤0.03%; the total content of other impurity elements ≤0.1%; and the balance is Al. This 6-series aluminum alloy sheet, with a low zinc content (Zn ≤0.10%), possesses excellent formability, high bake hardening value, and high batch stability.

This invention relates to the field of automotive steel technology, specifically to a 220MPa grade low-wavyness hot-dip galvanized bake-hardening steel sheet, its manufacturing method, and its application. The main chemical elements are C, Si, Mn, P, Als, Nb, N, and S. The dissolved C content in the steel is 0.0008%–0.0015%, with the balance being iron and unavoidable impurities. This invention also discloses a manufacturing method for the above-mentioned bake-hardening hot-dip galvanized steel sheet, including steelmaking, continuous casting, slab heating, hot rolling, laminar flow cooling, pickling, hot-dip galvanizing, and leveling processes. The surface waviness Wsa of the produced steel sheet after 5% forming is... (1‑5) ≤0.35μm, increase in surface waviness ΔWsa (1‑5) With a thickness of ≤0.05μm and a yield strength of 220~280MPa, it meets the application requirements of water-based no-primer coating process for automotive exterior body panels.

This invention relates to a cold-rolled steel sheet with high bake hardening and excellent bendability after bake hardening. It has a specified composition, containing 20%–70% ferrite and more than 30% tempered martensite by area ratio, with the total ferrite and tempered martensite exceeding 90%. A 30μm × 30μm microstructure image obtained by photographing the microstructure at 2000x magnification is placed in an xy coordinate system with the thickness direction as the x-axis and the rolling direction as the y-axis. The microstructure image is then divided into 1024 segments along the x-axis and 1024 segments along the y-axis to form 1024 × 1024 segmented regions. The values ​​in each segmented region are set to "1" if the microstructure is ferrite and "0" otherwise, and then converted to 2-grayscale to create a two-dimensional image. The heterogeneity α obtained by performing a two-dimensional discrete Fourier transform on the two-dimensional image is 1.20 or less.

An aspect of the present invention is to provide a cold-rolled steel sheet and a manufacturing method thereof. A preferred aspect of the present invention is to provide a cold-rolled steel sheet having excellent low-temperature bake hardenability and room-temperature aging resistance and a manufacturing method thereof.

This invention discloses a method for preparing high-strength and high-surface-quality 6xxx aluminum alloy outer plates, relating to the field of aluminum alloy manufacturing technology. It solves the problem of balancing bake-hardening strength, mechanical properties, and surface roughness of existing 6xxx aluminum alloy outer plates. The method includes melting and casting, ingot homogenization heat treatment, flat ingot machining, preheating, hot-rolled temperature-controlled rolling, cold-rolled rolling, intermediate annealing, cold-rolled rolling, solution quenching, and pre-aging treatment steps. This invention controls the intermediate billet temperature of the rough-rolled plate by controlling the rolling speed of the hot rough rolling, optimizing the material microstructure and regulating the texture type and distribution density. This results in a fine and uniform grain structure and a low proportion of Goss and Cube textures in the 6xxx aluminum alloy outer plate material. This ensures that no roughness morphology appears on the surface after stamping and oilstone polishing, and also improves the bake-hardening performance of the material, giving it high bake-hardening strength.

This invention provides a fine-grained, heat-stable, high-strength, and bake-hardening magnesium alloy and its preparation method, relating to the field of metal processing. This invention modifies the coarse Al-Mn phase into a high-density nanoscale Al-Mn-RE phase through RE microalloying. The heat resistance of the nanophase is improved through elemental phase boundary segregation, effectively enhancing the pinning effect of the nanoscale Al-Mn-RE phase. Co-segregation at coupled elemental grain boundaries further stabilizes the grain boundaries, suppressing grain coarsening during solid solution treatment. The average grain size can be stabilized at 2-15 micrometers. Furthermore, the density of the strengthening phase precipitated in the high-solid-solution microstructure after baking is extremely high, with a bake-hardening value ≥70 MPa, and some reaching over 90 MPa. The mechanical properties after baking are excellent, with a yield strength ≥260 MPa and an elongation ≥10%.