A double row tapered roller bearing includes: an outer ring having an annular shape; an inner ring disposed on an inner circumferential side of the outer ring and having an annular shape; and rollers. The inner ring has an outer circumferential surface facing the outer ring and having two rows of grooves having a bottom surface serving as a raceway surface. The rollers are tapered rollers disposed in the grooves in contact with the raceway surface of the inner ring and are also in contact with the outer ring. At outer circumferential surface of the inner ring, a region adjacent to the groove includes a hardened region extending from the inner peripheral surface of the groove to the region adjacent to the groove, and an unhardened region located at a position farther from the groove than the hardened region and being smaller in hardness than the hardened region.

A vehicle underbody assembly including a pair of rockers, a pair of side rails, a first cross member, a second cross member, and a fuel tank is provided. Each of the pair of side rails is secured to a rearward portion of one of the rockers. The first cross member extends between the side rails and is thermally treated to form a first central hard strength zone between two first soft strength zones. The second cross member is arranged with the pair of side rails and the first cross member to form a rectilinear frame and is thermally treated to form a second central hard strength zone between two second soft strength zones. The fuel tank is secured between the pair of side rails so that the fuel tank is located within a rectilinear frame formed by the pair of side rails and the cross members.

A vehicle component strength zone forming method is provided. The method includes identifying a condition of a blank via sensors at a furnace inlet. The method further includes outputting, by a controller, furnace command signals based on a predetermined thermal treatment schedule for the identified condition of the blank to heat a first blank portion to form a fully martensitic microstructure and heat a second blank portion to form a microstructure having one or more of ferrite, pearlite, and austenite. The method may further include outputting the furnace command signals based on furnace temperature variations detected by furnace sensors in communication with the controller. The method may further include outputting the furnace command signals based on one or more of a detected blank chemical composition, a detected type of blank coating, a detected blank thickness, and a detected blank material type.

A vehicle underbody assembly including a pair of rockers, a pair of rear rails, a first cross member, and a second cross member is provided. Each of the pair or rear rails extends from one of the rockers and each includes a rear portion, a first mid-portion, a second mid-portion, and a forward portion. Each of the forward portions is secured to one of the rockers at one of a first joint and a second joint. The first cross member extends between the rear rails at a transition region between the second mid-portion and the forward portion. The second cross member extends between the rear rails at locations adjacent the first and second joints. Each of the rear rails is thermally treated so that the second mid-portions form a hard strength zone. The hard strength zone may further be defined as a zone having a fully martensitic microstructure.

A bumper assembly may include a pair of crush cans and a bumper beam. The pair of crush cans are for securing to a vehicle body. The bumper beam is secured to the crush cans and includes a first end and a second end each extending outboard of one of the crush cans, and a middle portion extending between the first and second ends. The bumper beam is thermally treated to provide the first and second ends with less tensile strength than the middle portion. The middle portion may have a tensile strength between 1000 MPa and 1900 MPa. Each of the first and second ends may have a tensile strength between 600 MPa and 900 MPa.

A die apparatus including a first die element, a plurality of second die elements, a plurality of actuators, and a controller is provided. Each of the plurality of actuators is mounted to one of the plurality of second die elements. The controller is programmed to activate the actuators to contact and compress portions of a blank disposed between the die elements at separate pressures to influence microstructure forming for one of a geometry transition region, a deformation region, and a joining region. One of the separate pressures applied to one of the portions of the blank may be approximately 5 N/mm.sup.2 or less to form a soft strength zone. The pressure of approximately 5 N/mm.sup.2 or less may be applied to the one of the portions of the blank for approximately one to two seconds.

A dual pass seam welding method for steels having a Ceq of greater than about 0.45. The first pass welds the immediately anneals the weld. On the second pass, the welder is disengaged, and the weld is subjected to a second anneal.

A double row tapered roller bearing includes: an outer ring having an annular shape; an inner ring disposed on an inner circumferential side of the outer ring and having an annular shape; and rollers. The inner ring has an outer circumferential surface facing the outer ring and having two rows of grooves having a bottom surface serving as a raceway surface. The rollers are tapered rollers disposed in the grooves in contact with the raceway surface of the inner ring and are also in contact with the outer ring. At outer circumferential surface of the inner ring, a region adjacent to the groove includes a hardened region extending from the inner peripheral surface of the groove to the region adjacent to the groove, and an unhardened region located at a position farther from the groove than the hardened region and being smaller in hardness than the hardened region.

A method for processing a screw body, including a screw body providing step in which a screw body made of a hardenable steel is provided, a primary coating step, in which the screw body is coated with a primary coating that includes zinc, wherein the primary coating step follows the screw body providing step, and a tip hardening step, in which a tip region of the screw body, which is coated with the primary coating, is selectively heated, at least in part and with the ad-mission of oxygen, to a temperature required for hardening, characterized in that the tip hardening step follows the primary coating step. A screw that can be obtained using this method is also provided.

A connecting rod for a variable compression internal combustion engine, the connecting rod including a crank bearing eye for connecting the connecting rod with a crank shaft; a connecting rod bearing eye configured to connect the connecting rod with a cylinder piston of the internal combustion; an eccentrical element adjustment arrangement configured to adjust an effective connecting rod length, wherein the eccentrical element adjustment arrangement includes an eccentrical element that cooperates with an eccentrical element lever, wherein the eccentrical element is configured to receive a wrist pin of the cylinder piston, wherein the eccentrical element adjustment arrangement includes at least one cylinder with a piston that is displaceably supported in a cylinder bore hole and connected with a support rod, wherein the eccentrical element lever includes two eccentrical element lever segments which are connected by at least one connecting bolt to which the support rod is pivotably connected.