Provided are an alloy coating steel plate and a method of manufacturing the same, and in this case, the alloy coating steel plate includes a steel, and an Al—Mg—Si alloy layer positioned on the steel plate, wherein the Al—Mg—Si alloy layer is formed to include Mg—Si alloy grains in an alloy layer configured in an Al—Mg alloy phase.

A plated steel sheet includes: a steel sheet; and a plating layer that is formed on at least a part of a surface of the steel sheet, in which a chemical composition of the plating layer includes, by mass %, Al: more than 5.00% and 35.00% or less, Mg: 3.00% to 15.00%, Si: 0% to 2.00%, Ca: 0% to 2.00%, and a remainder of Zn and impurities, in which in a cross section of the plating layer in a thickness direction, the area ratio of a lamellar structure in which an (Al—Zn) phase and a MgZn.sub.2 phase are arranged in layers is 10% to 90%, a lamellar spacing of the lamellar structure is 2.5 μm or less, and the area ratio of an (Al—Zn) dendrite is 35% or less.

A pre-coated steel strip is provided. The steel strip includes a strip of base steel having a length, a width, a first side, and a second side. The length of the strip is at least 100 m and the width is at least 600 mm. An aluminum or an aluminum alloy pre-coating is on at least part of at least one of the first or second sides of the strip of base steel. A thickness t.sub.p of the pre-coating is from 20 to 33 micrometers at every location on at least one of the first or second sides. Processes, coated stamped products and land motor vehicles are also provided.

A press hardened coated steel part with high resistance to delayed fracture, the coating containing (Fe.sub.x—Al.sub.y) intermetallic compounds resulting from the diffusion of iron into an aluminum or an aluminum-based alloy, or an aluminum alloy of a precoating, wherein the chemical composition of the steel includes, in weight: 0.16%≤C≤0.42%, 0.1%≤Mn≤3%, 0.07%≤Si≤1.60%, 0.002%≤Al≤0.070%, 0.02%≤Cr≤1.0%, 0.0005≤B≤0.005%, 0.002%≤Mg≤0.007%, 0.002%≤Ti≤0.11%, 0.0008%≤O≤0.005%, wherein (Ti)×(O).sup.2×10.sup.7≤2, 0.001%≤N≤0.007%, 0.001%≤S≤0.005%, 0.001%≤P≤0.025% and optionally one or more elements selected from the list of: 0.005%≤Ni≤0.23%, 0.005%≤Nb≤0.060%, the remainder being Fe and unavoidable impurities, and wherein the microstructure includes at least 95% martensite.

A plated steel sheet having excellent chemical convertibility includes: a steel; and a plating layer that is provided on a surface of the steel, in which the plating layer includes, by mass %, Al: 5.00% to 35.00%, Mg: 2.50% to 13.00%, Fe: 5.00% to 35.00%, Si: 0% to 2.00%, Ca: 0.03% to 2.00%, and a remainder consisting of Zn and impurities, and in a surface of the plating layer, the area fraction of a Fe—Al phase is 0% to 30%, the area fraction of a rod-like lamellar structure of Zn and MgZn.sub.2 is 5% to 90%, the area fraction of a massive MgZn.sub.2 phase is 10% to 70%, and the area fraction of a remainder is 10% or less.

A process for manufacturing a press hardened steel part is provided. The steel of the part has a chemical composition including, in weight: 0.062%≤C≤0.095%, 1.4%≤Mn≤1.9%, 0.2%≤Si≤0.5%, 0.020%≤Al≤0.070%, 0.02%≤Cr≤0.1%, wherein: 1.5%≤(C+Mn+Si+Cr)≤2.7%, 0.040%≤Nb≤0.060%, 3.4×N≤Ti≤8×N wherein: 0.044%≤(Nb+Ti)≤0.090%, 0.0005≤B≤0.004%, 0.001%≤N≤0.009%, 0.0005%≤S≤0.003%, 0.001%≤P≤0.020%, optionally: 0.0001%≤Ca≤0.003%, and the remainder being Fe and unavoidable impurities. The process includes hot forming the heated blank in the forming press so as to obtain a formed part and cooling the formed part at a cooling rate CR1 between 40 and 360°C/s in a temperature range from 750 to 450°C. and at a cooling rate CR2 between 15 to 150°C/s in a temperature range from 450°C to 250°C. wherein CR2<CR1.

Provided is a steel sheet for a hot press formed member having excellent resistance to hydrogen delayed fracture, and a method for manufacturing the same. A steel sheet for a hot press formed member comprises: a base steel sheet; an aluminum alloy plating layer on a surface of the base steel sheet; and an oxide layer which is formed on a surface of the plating layer and has a thickness of 0.05 μm or more.

A method of resistance spot welding a stacked assembly of dissimilar workpieces. The stack assembly includes a first workpiece formed of a first alloy, a second workpiece formed of a second alloy, and a third workpiece formed of a third alloy sandwiched between the first workpiece and the second workpiece. The third alloy includes a lower resistivity than the first alloy and a lower resistivity than the second alloy. A faying interface is defined by a portion of the first workpiece in direct contact with a portion of the second workpiece through the third workpiece. A weld nugget, a braze, or a combination of a weld nugget and a braze joins the first workpiece to the second workpiece at the faying interface. An annular ring of re-solidified molten pool of third alloy surrounds the faying interface and a region of re-solidified partially melted third alloy surrounding the annular ring.

A method of forming a hollow structure in an additively manufactured object involves creating a pattern on a surface of a base material of the object with a sacrificial metal filler having a melting point of 350° C. or less, the pattern defining a shape of the hollow structure on the base material. A metal layering material is cold sprayed over the sacrificial metal filler and at least a portion of the base material. The sacrificial metal filler is removed from the pattern by melting the sacrificial metal filler without melting or deforming the base material or the metal layering material to leave the hollow structure in the object formed from the pattern. Non-standard cold spray conditions are used with the metal layering material to prevent damage and or displacement of the filler while still forming a coating of the metal layering material on the filler and base material.

The present invention relates to a method for the manufacture of a galvannealed steel sheet including the steps of A.) coating of the steel sheet with a first coating consisting of nickel and having a thickness between 150 nm and 650 nm, the steel sheet having the following composition in weight percentage 0.10<C<0.40%, 1.5<Mn<3.0%, 0.7<Si<3.0%, 0.05<Al<1.0%, 0.75<(Si+Al)<3.0%, and on a purely optional basis, one or more elements such as Nb≤0.5%, B≤0.010%, Cr s 1.0%, Mo≤0.50%, Ni≤1.0%, Ti≤0.5%., the remainder of the composition is made up of iron and inevitable impurities resulting from the elaboration, B.) annealing of the coated steel sheet being annealed at a temperature between 600 to 1200° C., C.) coating of the steel sheet obtained in step B.) with a second coating based on zinc and D.) an alloying heat treatment to form a galvannealed steel sheet.