One aspect of the disclosure provides an iron-based hardfacing layer which includes hard or wear resistant phases resulting at least in part from dissolution of silicon and/or boron carbide particles into a liquid iron-based metal during the fabrication process. In an embodiment, the hardfacing layer is formed by a fusion welding process in which carbide particles are added to the molten weld pool. In an example, the filler metal supplied to the welding process is a mild steel. In an embodiment, the hardness as measured at the surface of the hardfacing ranges from 40 to 65 HRC. In an example, the iron-based hardfacing layer also includes tungsten carbide particles.

Weld metals and methods for welding ferritic steels are provided. The weld metals have high strength and high ductile tearing resistance and are suitable for use in strain based pipelines. The weld metal contains retained austenite and has a cellular microstructure with cell walls containing lath martensite and cell interiors containing degenerate upper bainite. The weld metals are comprised of between 0.02 and 0.12 wt % carbon, between 7.50 and 14.50 wt % nickel, not greater than about 1.00 wt % manganese, not greater than about 0.30 wt % silicon, not greater than about 150 ppm oxygen, not greater than about 100 ppm sulfur, not greater than about 75 ppm phosphorus, and the balance essentially iron. Other elements may be added to enhance the properties of the weld metal. The weld metals are applied using a power source with current waveform control which produces a smooth, controlled welding arc and weld pool in the absence of CO.sub.2 or oxygen in the shielding gas.

A welded steel part with a very high mechanical strength is provided. The welded steel part is obtained by heating followed by hot forming, then cooling of at least one welded blank obtained by butt welding of at least one first and one second sheet. The at least one first and second sheets including, at least in part, a steel substrate and a pre-coating which includes an intermetallic alloy layer in contact with the steel substrate, topped by a metal alloy layer of aluminum or aluminum-based alloy. A method for the fabrication of a welded steel part and the fabrication of structural or safety parts for automotive vehicles are also provided.

A welded steel part with a very high mechanical strength is provided. The welded steel part is obtained by heating followed by hot forming, then cooling of at least one welded blank obtained by butt welding of at least one first and one second sheet. The at least one first and second sheets including, at least in part, a steel substrate and a pre-coating which includes an intermetallic alloy layer in contact with the steel substrate, topped by a metal alloy layer of aluminum or aluminum-based alloy. A method for the fabrication of a welded steel part and the fabrication of structural or safety parts for automotive vehicles are also provided.

A filler for welding including (in % by weight): C: ≦0.036, Ni: 15.0-20.0, Cr: 15.0-22.0, Mn: 0.75-2.0, Zr: 0.1-1.45, Si: 0-1.5, Al: 0-2, N: <0.06, and a balance of Fe and inevitable impurities.

A flux-cored wire for gas-shielded arc welding has a steel outer sheath filled with a flux. The flux-cored wire includes specific amounts, relative to a total mass of the wire, of TiO.sub.2, at least one of Si, an Si oxide and an Si compound, C, Mn, Mo, Ni, at least one of metal Mg and an Mg alloy, an F compound, a K compound, an Na compound, B and a B compound, and Fe, respectively. A total content of each of Ti and a Ti alloy, metal Al and an Al alloy, and V is restricted to the specific range, respectively. A content of Ti is also restricted to the specific range relative to the total mass of the steel outer sheath.

A method of resistance spot welding a workpiece stack-up that includes an aluminum workpiece and an overlapping adjacent steel workpiece so as to minimize the thickness of an intermetallic layer comprising Fe—Al intermetallic compounds involves providing reaction-slowing elements at the faying interface of the aluminum and steel workpieces. The reaction-slowing elements may include at least one of carbon, copper, silicon, nickel, manganese, cobalt, or chromium. Various ways are available for making the one or more reaction-slowing elements available at the faying interface of the aluminum and steel workpieces including being dissolved in a high strength steel or being present in an interlayer that may take on a variety of forms including a rigid shim, a flexible foil, a deposited layer adhered to and metallurgically bonded with a faying surface of the steel workpiece, or an interadjacent organic material layer that includes particles containing the reaction-slowing elements.

A method of manufacturing includes depositing a braze filler adjacent to a void between a first component and a second component thus holding the components in position before brazing. The first and second components are heated to melt and flow the braze filler into the void. A braze joint is formed between the first and second components by cooling the braze filler. Depositing the braze filler can include laser cladding the braze filler to the first and/or second components adjacent the void. The method also optionally includes welding the first and second components in position with the braze filler adjacent to the void. The braze filler may be deposited as a powder, cold spray, melted brazed filament, spherical ball or any other suitable form.

The present invention concerns a new metal powder which is useful for coating cast iron parts. The invention also relates to a method for coating cast iron parts by using the new metal powder. Of special importance is the possibility to use the metal powder for coating the surfaces of glass moulds. The invention also relates to metal parts, such as cast iron parts, or glass moulds which are coated by the metal powder.

A brazed heat exchanger includes plates that are stacked or nested to define flow channels for multiple media. Inserts are arranged within at least some of the flow channels. Two different braze alloys having compositions based on different metals are used to form braze joints between the plates and the inserts. In some cases, a copper-based braze alloy is used for joints corresponding to flow channels for one of the media in order to provide high pressure-resisting strength to those flow channels, while an iron-based braze alloy is used for joints corresponding to flow channels for another of the media where dissolved copper is undesirable.