The present invention relates to methods and apparatus for detection of fire states in the presence of welding activities. In some examples, the welding detection system may algorithmically calculate a risk of a fire state developing. In some embodiments, the welding fire detection and prevention system may communicate warning states to users, supervisors, equipment and/or building monitoring systems.

A composite component includes a reinforcement bonded to a base component by a bond formed by, or reinforced with, a localized coupling in the base component. The bond may be formed by ultrasonic additive manufacturing. The localized coupling may include a compression of the base component, a weld in the base component, or a heat affected zone of the weld. Where the bond is formed by the localized coupling, the localized coupling encompasses the reinforcement. Where the bond is reinforced with the localized coupling, the localized coupling may encompass the reinforcement, or be arranged at an inside radius of a turn in the reinforcement. The reinforcement results in the composite component having enhanced properties such as lower density, increased strength, stiffness, or energy absorption capabilities.

This joint component is a joint component including a first steel member, a second steel member, and a spot-welded portion that joins the first steel member and the second steel member, in which the first steel member includes a steel sheet substrate having a predetermined chemical composition and a coating that is formed on a surface of the steel sheet substrate, contains Al and Fe, and has a thickness of 25 μm or more, in a cross section in a thickness direction of the first steel member and the second steel member including the spot-welded portion, a filled metal containing Al and Fe is present in a gap between the first steel member and the second steel member in a periphery of the spot-welded portion, in the cross section, the filled metal has a cross-sectional area of 3.0×10.sup.4 μm.sup.2 or more, and has a filling ratio of 80% or more in the gap in a range of 100 μm from an end portion of a corona bond formed in the periphery of the spot-welded portion, and includes a first region and a second region.

This joint component is a joint component including a first steel member, a second steel member, and a spot-welded portion that joins the first steel member and the second steel member, in which the first steel member includes a steel sheet substrate having a predetermined chemical composition and a coating that is formed on a surface of the steel sheet substrate, contains Al and Fe, and has a thickness of 25 μm or more, in a cross section in a thickness direction of the first steel member and the second steel member including the spot-welded portion, a filled metal containing Al and Fe is present in a gap between the first steel member and the second steel member in a periphery of the spot-welded portion, in the cross section, the filled metal has a cross-sectional area of 3.0×10.sup.4 μm.sup.2 or more, and has a filling ratio of 80% or more in the gap in a range of 100 μm from an end portion of a corona bond formed in the periphery of the spot-welded portion, and includes a first region and a second region.

A resistance spot welding method for spot welding plural steel sheets including at least one galvanized steel sheet containing 0.08 mass % or more of C and 0.50 mass % or more of Si and having a tensile strength of 980 MPa or more, the resistance spot welding method includes, using a pair of electrodes including a pair of electrode tips configured to sandwich and pressurize the plural steel sheets and a pressurizing force absorbing mechanism provided in at least one of the pair of electrode tips and capable of absorbing a pressurizing force in an axial direction of the electrode tips, welding by sandwiching the plural steel sheets between the pair of electrode tips and energizing the pair of electrode tips with a pressurizing force applied, while absorbing a fluctuation load of the pressurizing force generated during the energization by the pressurizing force absorbing mechanism.

A resistance welder, which includes a clamp for supporting a detachable arm, the arm being constituted by a fixed part supporting a fixed electrode and a rotationally mobile part supporting a mobile electrode. The electrodes are intended to be crossed by an electrical current. The mobile arm of the clamp is pushed in its rotational motion by a thruster so that the extremities of the electrodes approach each other and grip the elements to be welded. The clamp further includes a shift measurement sensor, the value measured by this sensor being proportional to the distance between the extremities of the electrodes. It is thus easy to measure the distance between the electrodes and the measurement made on the piston can be used for other types of arms.

A resistance spot welding method includes the steps of: removing at least part of oil on a surface of a welding target material by energization between a pair of electrodes; and after the oil removal step, forming a nugget in an overlapped portion of the welding target material by energization between the pair of electrodes.

In a vehicle body structure, an end portion of a first vehicle body member having a plate shape is coupled to a second vehicle body member having a plate shape. The first vehicle body member is made of a first metal and the second vehicle body member is made of a second metal. The vehicle body structure includes a third vehicle body member made of the first metal. The third vehicle body member includes an interposed portion having general portions and a convex portion. The convex portion has a weld-joint portion configured to be joined to the end portion of the first vehicle body member by welding. Each of the general portion has a swage-joint portion configured to be swaged and jointed to the second vehicle body member in a circular shape viewed from a thickness direction, and a cutout portion.

A method for producing a zinc or zinc-alloy coated steel sheet with a tensile strength higher than 900 MPa, for the fabrication of resistance spot welds containing in average not more than two Liquid Metal Embrittlement cracks per weld having a depth of 100 μm or more, with steps of providing a cold-rolled steel sheet, heating cold-rolled steel sheet up to a temperature T1 between 550° C. and Ac1+50° C. in a furnace zone with an atmosphere (A1) containing from 2 to 15% hydrogen by volume, so that the iron is not oxidized, then adding in the furnace atmosphere, water steam or oxygen with an injection flow rate Q higher than (0.07%/h×α), α being equal to 1 if said element is water steam or equal to 0.52 if said element is oxygen, at a temperature T≥T1, so to obtain an atmosphere (A2) with a dew point DP2 between −15° C. and the temperature Te of the iron/iron oxide equilibrium dew point, then heating the sheet from temperature T.sub.1 up to a temperature T.sub.2 between 720° C. and 1000° C. in a furnace zone under an atmosphere (A2) of nitrogen containing from 2 to 15% hydrogen and more than 0.1% CO by volume, with an oxygen partial pressure higher than 10.sup.−21 atm., wherein the duration t.sub.D of heating of the sheet from temperature T.sub.1 up to the end of soaking at temperature T.sub.2 is between 100 and 500 s., soaking the sheet at T.sub.2, then cooling the sheet at a rate between 10 and 400° C./s, then coating the sheet with zinc or zinc-alloy coating.

Disclosed are aluminum alloy products and methods of making and processing such products. Thus, disclosed are aluminum alloy products exhibiting controllable surface properties, including excellent bond durability, low contact resistance, and corrosion resistance. Aluminum alloy products described herein include a migrant element, a subsurface portion having a concentration of the migrant element, and a bulk portion having a concentration of the migrant element. The aluminum alloy product comprises an enrichment ratio of 4.0 or less, wherein the enrichment ratio is a ratio of the migrant element concentration in the subsurface portion to the concentration in the bulk portion. Additionally, the aluminum alloy products surface and/or subsurface can contain phosphorus (e.g., elemental phosphorus or oxidized phosphorus). The phosphorus containing surface provides reduced electronic stress on an electrode tip of a resistance spot welding apparatus, and an extended service lifetime (e.g., weld cycles to failure) of the electrode tip.