A method of generating compressive residual stresses through a thickness of a metal component comprising the steps: receiving a metal base component (10), which in use is subjected to applied pressure and applying by thermal deposition cladding (16) to one or more surfaces (14) of the base component. The cladding (16) comprises one or more layers of metal or metal alloy. The method also includes, subsequent to the cladding step, applying autofrettage to the clad component thereby generating compressive residual stresses through the one or more layers of metal or metal alloy (16) and at least part way through the base component.

The present invention relates to a motor vehicle crash box with a working direction in vehicle's longitudinal axis manufactured out of a tube which is expanded into different zones, wherein the zones are different in strength and diameter by using steel after forming a homogenous austenitic microstructure with a strain hardening effect. The present invention further relates to the manufacturing method of such a component.

A process for treating a centrifugal compressor wheel includes a combination of cold expansion of at least part of the bore of the wheel to induce residual compressive stresses in a region around the bore, and surface peening at least parts of the compressor wheel such as the back disk and portions of the blades.

A steel pipe for pressure piping can be subjected to autofrettage. When an outer diameter of the pipe is D, an inner diameter is d, and a yield stress is σ.sub.y, and when a measured value of an outer surface residual stress is σ.sub.o1, a measured value of an outer surface residual stress after halving is σ.sub.o2, and a measured value of an inner surface residual stress after the halving is σ.sub.i2, D/d is 1.2 or more, an estimated value σ.sub.i1 of inner surface residual stress is [σ.sub.i1=(−σ.sub.i2)/(A×(t/T).sup.2−1)], where [t/T=((σ.sub.o2−σ.sub.o1)/(A×(σ.sub.o2−σ.sub.o1)−C×σ.sub.i2)).sup.1/2], [A=3.9829×exp(0.1071×(D/d).sup.2)], and [C=−3.3966×Exp(0.0452×(D/d).sup.2)] satisfies [1.1×F×σ.sub.y≤α.sub.i1≤0.8×F×σ.sub.y], and (F=(0.3×(3−D/d).sup.2−1) when 1.2≤D/d≤3.0, and F=−1 when D/d>3.0).

A process for preparing a multi-thickness welded steel vehicle rail, the process comprises the steps of: (a) forming a first tube having a first outer diameter, an inner diameter and a first wall thickness; (b) forming a second tube having the first outer diameter, a second inner diameter and a second wall thickness different than the first wall thickness; (c) swaging a first end of the first tube to a second outer diameter less than the second inner diameter of the second tube; (d) inserting the swaged first end of the first tube into an end of the second tube to form a joint; (e) welding the first tube and the second tube together to form a weld at the joint to form a tube blank with a heat affected zone of lower metal strength in the area of the weld; (f) preheating the tube blank to create a common crystalline microstructure along a length of the tube blank; (g) introducing the tube blank into a blow molding tool having inner molding walls; (h) molding the tube blank at an elevated temperature by expanding the tube blank against the inner molding walls of the molding tool by injecting a pressurized medium into an interior cavity of the tube blank; and (i) quenching the tube blank by replacing the pressurized medium with a cooling medium through the molding tool and the tube blank to achieve a rapid cooling effect on the tube blank and to create a completed vehicle rail with essentially uniform material strength across the weld. A completed vehicle rail has an overlapped welded structure and uniform microcrystalline structure along the length of the rail.

The invention is directed to a method for improving the fatigue behavior of the body (2) of a gas valve, the body comprising at least two bores (4, 10) and at least one bore intersection (20) defining an internal volume; wherein the method comprises the following step: subjecting the internal volume to an autofrettage by applying a pressure of comprised between 100 MPa and 500 MPa by means of a liquid. 10. The invention is also directed to a gas valve body (2) comprising at least two bores (4, 10) and at least one bore intersection (20) defining an internal volume with an internal wall; wherein the internal wall is treated by autofrettage resulting in compressive stresses at the intersection or at least one of the intersections.

The invention is directed to a method for improving the fatigue behavior of the body (2) of a gas valve, the body comprising at least two bores (4, 10) and at least one bore intersection (20) defining an internal volume; wherein the method comprises the following step: subjecting the internal volume to an autofrettage by applying a pressure of comprised between 100 MPa and 500 MPa by means of a liquid. 10. The invention is also directed to a gas valve body (2) comprising at least two bores (4, 10) and at least one bore intersection (20) defining an internal volume with an internal wall; wherein the internal wall is treated by autofrettage resulting in compressive stresses at the intersection or at least one of the intersections.

The present invention relates to delivering sand to a metal melting furnace to fill a tap hole. The swiveling sander moves into position through a horizontal arcing movement. The Swiveling Sanding Systems comprises a swiveling sander with slag plunger. The Swiveling Sander swivels from a home position into a sanding position in order to add sand to a metal melting furnace at the same time as the slag plunger moves out of the way. After delivering sand, the swiveling sander swivels back to home position while the slag plunger also moves back to home position followed by the plunger clearing any slag.

A process for preparing a multi-thickness welded steel vehicle rail, the process comprises the steps of: (a) forming a first tube having a first outer diameter, an inner diameter and a first wall thickness; (b) forming a second tube having the first outer diameter, a second inner diameter and a second wall thickness different than the first wall thickness; (c) swaging a first end of the first tube to a second outer diameter less than the second inner diameter of the second tube; (d) inserting the swaged first end of the first tube into an end of the second tube to form a joint; (e) welding the first tube and the second tube together to form a weld at the joint to form a tube blank with a heat affected zone of lower metal strength in the area of the weld; (f) preheating the tube blank to create a common crystalline microstructure along a length of the tube blank; (g) introducing the tube blank into a blow molding tool having inner molding walls; (h) molding the tube blank at an elevated temperature by expanding the tube blank against the inner molding walls of the molding tool by injecting a pressurized medium into an interior cavity of the tube blank; and (i) quenching the tube blank by replacing the pressurized medium with a cooling medium through the molding tool and the tube blank to achieve a rapid cooling effect on the tube blank and to create a completed vehicle rail with essentially uniform material strength across the weld. A completed vehicle rail has an overlapped welded structure and uniform microcrystalline structure along the length of the rail.

A steel pipe or tube for pressure vessels having excellent quench crack resistance is provided. The steel pipe or tube for pressure vessels comprises: a specific chemical composition; and a metallic microstructure in which an average grain size of prior austenite grains is 500 μm or less, and an area fraction of microstructures other than ferrite is 50% or more.