Abstract: A superplastically deformable aluminium base alloy contains 2-8.5% by weight of magnesium and 0.4-1% by weight chromium. It may also contain minor alloying elements.

Abstract: An internal member for supporting a hollow body during shearing in the form of a close-fitting solid body. The body comprises at least portions meeting in the shearing plane and each portion including at least one split ring having a single gap in its periphery to allow it to expand to fit the hollow body. Expansion may be effected by axial movement of frusto-conical plugs corresponding to and co-operating with frusto-conical inner surface in the rings. Each ring may either comprise a single component, preferably notched on its inner face to increase flexibility, or be in the form of a thin split cylindrical shell surrounding a plurality of inner segments.

Abstract: Improved optical means for automatically controlling or monitoring the position of a relatively moving member such as a tool tip in a numerically controlled machine tool has an image of a region of a datum line projected on to a slit in an optical system. Light passing through the slit falls on to a photoelectric detector device which comprises an array of discrete elements. The elements are electronically scanned sequentially and an electric circuit is provided to produce an output signal when a preset change in incident light intensity is detected by any of the photoelectric elements thus indicating the presence of the movable member at the datum line. There may be two slits projecting images of the region around two transverse datum lines on to two separate arrays so that the movable member can be controlled in two dimensions. Alternatively, in place of two separate arrays and two slits a single two dimensional array may be provided suitably masked.

Abstract: It has now been found that alloys of the type that are the cheapest and most widely used for the production of formed components may also be provided with superplastic properties. Such alloys may comprise a selected non-heat treatable base material together with dynamic recrystallization modifying additives to achieve fine structure. The base material may be aluminium of normal commercial purity and the additives 0.4% to 2% iron and 0.4 to 2% silicon; or the base material may be aluminium and 0.75 to 2.5% manganese and the additive 0.4 to 1% iron; or the base material may be aluminium and 0.25 to 0.75% manganese with no additive; or the base material may be aluminium and 1 to 4% magnesium and the additive 0.25 to 0.75% manganese. In all these cases at least one of the elements Zr, Nb, Ta and Ni must also be present in an amount of at least 0.3% substantially all of which is in solid solution and the total amount of said elements not exceeding 1%.

Abstract: A method of orbital shearing of elongated stock such as tube stock comprises passing the stock through aligned dies, then causing relative lateral displacement, arcuate or linear, between the axes of dies, and causing a relative orbital movement between one die and the stock held in the other die. The lateral movement causes partial shearing, which is propagated around the stock by the orbital movement. One die may be fixed, while the other performs both the lateral and then the orbital movement. The stock may be rotated, in which case the moving die only has to move laterally to achieve the orbital movement as well.

Abstract: Alloys having a composition suitable for superplastic deformation usually require heat treatment after casting and mechanical working in order to produce in the alloy the necessary fineness of grain stucture to permit such deformation to occur. It has now been found that some such alloys including in particular ranges of aluminum alloys containing zirconium (or Nb, Ta or Ni) may be heated to a superplastic forming temperature and non-superplastically deformed at that temperature to induce dynamic recrystallisation and simultaneously produce a fine recrystallised grain structure and superplastic deformation.

Abstract: Aluminum-base wrought products containing the elements normally present in either non-heat treatable aluminium-base alloys of at least 5%Mg or at least 1%Zn or heat-treatable aluminium-base alloys of one or more of the elements Cu, Mg, Zn, Si, Li and Mn in known combinations, and at least one of the elements Zr, Nb, Ta and Ni in a total amount of at least 0.30% substantially all of which is present in solid solution, are superplastically deformable. The remainder of the superplastically deformable product may be the normal impurities and incidental elements known to be incorporated in heat-treatable and non-heat treatable aluminium-base alloys. Advantageously the alloy of the wrought product contains at least 0.3%Zr and preferably at least 0.40%Zr.

Abstract: In tube-shearing apparatus of the kind employing relatively transversely moving apertured dies and an internal supporting mandrel, the mandrel comprises an elastomeric body which is compressed axially with the high force to expand it radially against the tube wall such as to form not merely an internal support but effectively a supporting shear blade inside the tube. This allows clean shearing also of tubes having internal protuberances such as welding seams.