Explosive treatment of metals
Explosive welding of metals
The focus of activities in the explosive welding of metals is on developing and producing explosion-welded bimetallic and multilayer metallic materials. Semi-finished products and construction parts are usually manufactured in direct cooperation with the customer. An explosion can be used to weld a broad range of metals, including metals with a low melting point such as lead or tin. The necessary condition for accomplishing explosive welding is the ductility of metals, which should optimally be above 10%. The surfaces of metals intended for explosive welding are prepared by ordinary machining, mechanical or manual grinding and do not require any special treatment.
Semi-finished tube sheets for heat exchangers
They are manufactured in combinations of carbon and low-alloy steels with corrosion-resistant steels, copper and its alloys, titanium, aluminium and its alloys, nickel and its alloys etc. They can be clad on one side or on both sides, as a rule, throughout the surface. In some cases, fusion welding on local areas can be combined advantageously with the final layer being welded on through explosive welding. Increased layers of welded-on metal can thus be provided in selected parts of the component.
Bimetallic or multilayer metal sheets
Materials for the manufacture of vessels in the chemical, food-processing and energy industries are produced in similar combinations as semi-finished tube sheets. Multilayer materials are produced for special purposes according to the customer’s requirements. Area dimensions and thicknesses of welded metallic semi-finished products need to be discussed at all times. Sputtering targets are prepared in the form of metal sheets or circular plates as well.
Bearing materials and abrasion-resistant materials
Sliding alloys (aluminium and tin bronzes) clad on to a base of carbon steel in the form of a sheet or strip. The result includes semi-finished products for the curling of bearing shells, guide bars, bearing plates, semi-finished elements for hydraulic components etc.
A traditional abrasion-resistant material – Hadfield steel – is usually clad on to structural carbon steel, which makes it possible to weld it to steel structures afterwards using standard methods without any difficulty. In addition to conventional abrasion-resistant materials, some tool steels or other materials featuring increased hardness and strength can be clad as well. Nevertheless, the materials are always clad in their initial annealed state, sometimes complemented by a suitable interlayer allowing subsequent thermal processing of such a multilayer structure.
A traditional abrasion-resistant material – Hadfield steel – is usually clad on to structural carbon steel, which makes it possible to weld it to steel structures afterwards using standard methods without any difficulty. In addition to conventional abrasion-resistant materials, some tool steels or other materials featuring increased hardness and strength can be clad as well. Nevertheless, the materials are always clad in their initial annealed state, sometimes complemented by a suitable interlayer allowing subsequent thermal processing of such a multilayer structure.
Semi-finished products for expansion
Blanks clad on one side or both sides intended for subsequent expansion in hot or cold conditions are prepared in combinations of carbon steels with corrosion-resistant materials, titanium, copper and its alloys or nickel and its alloys. This category includes combinations of various copper and silver alloys for use in electrical engineering.
Transition pieces
Bimetallic or multilayer construction parts for subsequent fusion welding between conventionally unweldable materials. The most common combination is carbon steel - aluminium and the combination of copper and aluminium for electrotechnical purposes, or transition pieces for connecting the steel structure of a boat to the aluminium elements of the deck, and a combination of metals for use in cryogenics. Tubular intermediate pieces can be prepared as well.
Semi-finished glass moulds
They are produced in the form of slabs, blocks and discs with one side clad with pure nickel or high-alloy chromium-nickel austenitic steel. As a rule, the base material is soft structural carbon steel. It is possible to suitably combine the durability of the functional layer with the thermal conductivity of the substrate, while making significant savings of nickel and its alloys. Semi-finished products prepared in this way are used most widely in the manufacture of moulds for the manual pressing of glass stones.
Explosive welding and fixing of pipes
Explosive welding and explosive fixing of pipes for their subsequent welding into tube sheets in various material and geometrical combinations. The benefit is, in particular, that the pipe can be fixed or welded in the width of the tube sheet.
Labyrinth coolers
Explosive cladding of copper or steel plates with a milled labyrinth of a random shape is used to prepare coolers of a slab-like (or cylindrical) shape, for example, for continuous and semi-continuous casting of non-ferrous metals or steel. Its benefit lies in more efficient cooling thanks to an optimised shape and distribution of cooling ducts in close proximity to the cooler’s surface.
Coating of flanges and plating of rods or shafts
The application of explosive welding in rotational symmetry makes it possible to cover the surface of a cylindrical opening or the outer surface of a cylindrical rod with the selected material. The most frequent applications include the coating of flanges with corrosion-resistant materials. In particular, this concerns situations where fusion welding cannot be employed or the diameter and length of the opening do not allow using a conventional technique for overlaying. Shafts can be clad, for example, with a suitable sliding material. Bimetallic rods of a circular cross-section can be prepared in various material combinations.
