A press hardening method including: A. provision of a steel sheet for heat treatment, being optionally precoated with a zinc- or aluminum-based pre-coating, B. deposition of a hydrogen barrier pre-coating comprising chromium and not comprising nickel over a thickness from 10 to 550 nm, C. cutting of the precoated steel sheet to obtain a blank, D. heat treatment of the blank at a furnace temperature from 800 to 970° C., during a dwell time from 1 to 12 minutes, in an atmosphere having an oxidizing power equal or higher than that of an atmosphere consisting of 1% by volume of oxygen and equal or smaller than that of an atmosphere consisting of 50% by volume of oxygen, such atmosphere having a dew point between −30 and +30° C., E. transfer of the blank into a press tool, F. hot-forming at a temperature from 600 to 830° C. to obtain a part, G. cooling of the part obtained at step E).

A method for processing corrosion resistant austenitic stainless steel includes: preparing a workpiece made of austenitic stainless steel; and applying compressive residual stress to a surface layer of the workpiece without subjecting the surface layer to plastic working.

Described is a method of modifying material properties of a workpiece using a high-pressure-torsion apparatus, comprising a working axis, a first anvil, a second anvil, and an annular body, comprising a first recirculating convective chiller, a second recirculating convective chiller, and a heater, positioned between the first recirculating convective chiller and the second recirculating convective chiller along the working axis. The method comprises compressing the workpiece along a central axis of the workpiece and. simultaneously with compressing the workpiece along the central axis, twisting the workpiece about the central axis. The method further comprises. while compressing the workpiece along the central axis and twisting the workpiece about the central axis, translating the annular body along the working, axis of the high-pressure-torsion apparatus, collinear with the central axis of the workpiece, and heating the workpiece with the heater.

Described is a method of modifying material properties of a workpiece using a high-pressure-torsion apparatus, comprising a working axis, a first anvil, a second anvil, and an annular body, comprising a first total-loss convective chiller, a second total-loss convective chiller, and a heater, positioned between the first total-loss convective chiller and the second total-loss convective chiller along the working axis. The method comprises compressing the workpiece along a central axis of the workpiece and, simultaneously with compressing the workpiece along the central axis, twisting the workpiece about the central axis. The method further comprises, while compressing the workpiece along the central axis and twisting the workpiece about the central axis, translating the annular body along the working axis of the high-pressure-torsion apparatus, collinear with the central axis of the workpiece, and heating the workpiece with the heater.

Described is a method of modifying material properties of a workpiece using a high-pressure-torsion apparatus, comprising a working axis, a first anvil, a second anvil, and an annular body, comprising a first conductive chiller, a second conductive chiller, and a heater, positioned between the first conductive chiller and the second conductive chiller along the working axis. The method comprises compressing the workpiece along a central axis of the workpiece and, simultaneously with compressing the workpiece alone the central axis, twisting the workpiece about the central axis. The method further comprises, while compressing the workpiece along the central axis and twisting the workpiece about the central axis, translating the annular body along the working axis of the high-pressure-torsion apparatus, collinear with the central axis of the workpiece, and heating the workpiece with the heater.

A high-pressure-torsion apparatus (100), comprising a working axis (102), a first anvil (110), a second anvil (120), and an annular body (130). The annular body (130) comprises a first total-loss convective chiller (140), a second total-loss convective chiller (150), and a heater (160). Each of the first total-loss convective chiller (140) and the second total-loss convective chiller (150) is translatable between the first anvil (110) and the second anvil (120) along the working axis (102), is configured to be thermally convectively coupled with a workpiece (190), and is configured to selectively cool the workpiece (190). The heater (160) is positioned between the first total-loss convective chiller (140) and the second total-loss convective chiller (150) along the working axis (102), is translatable between the first anvil (110) and the second anvil (120) along the working axis (102), and is configured to selectively heat the workpiece (190).

A high-pressure-torsion apparatus (100) comprises a working axis (102), a first anvil (110), a second anvil (120), and an annular body (130). The annular body (130) comprises a first conductive chiller (140), a second conductive chiller (150), and a heater (160). Each of the first conductive chiller (140) and the second conductive chiller (150) is translatable between the first anvil (110) and the second anvil (120) along the working axis (102), is configured to be thermally conductively coupled with a workpiece (190), and is configured to selectively cool the workpiece (190). The heater (160) is positioned between the first conductive chiller (140) and the second conductive chiller (150) along the working axis (102), is translatable between the first anvil (110) and the second anvil (120) along the working axis (102), and is configured to selectively heat the workpiece (190).

A high-pressure-torsion apparatus (100) comprises a working axis (102), a first anvil (110), a second anvil (120), and an annular body (130). The annular body (130) comprises a a first recirculating convective chiller (140), a second recirculating convective chiller (150), and a heater (160). Each of the first recirculating convective chiller (140) and the second recirculating convective chiller (150) is translatable between the first anvil (110) and the second anvil (120) along the working axis (102), is configured to be thermally convectively coupled with a workpiece (190), and is configured to selectively cool the workpiece (190). The heater (160) is positioned between the first recirculating convective chiller (140) and the second recirculating convective chiller (150) along the working axis (102), is translatable between the first anvil (110) and the second anvil (120) along the working axis (102), and is configured to selectively heat the workpiece (190).

The present invention relates to a reinforced bulging tank of a launch vehicle and a manufacturing method therefor. The tank is made of metal material with good plasticity. Firstly, the tank is manufactured by welding annealed plastic metal materials, wherein internal longitudinal reinforcing ribs and internal annular frames/annular plates of barrel sections are welded with a barrel section shell by a low energy laser welding method, and tank bottoms are progressively welded by a plurality of conical sections. Weldments are strengthened and formed through internal pressure bulging under the constraint of external tooling. The outer walls of the barrel sections are not radially deformed under the constraint of a plurality of small width metal rings, and the metal rings are not connected to each other axially. The strength of the materials can be greatly improved by a deep cooling bulging technology.