-(220-x-200-px)-(130-x-130-px)-(220-x-200-px).jpg?lang=en-US&ext=.jpg)
Veolia.gif?width=200&height=200&mediaprotectionhash=4deca34a0d5a00013b5a0ccdc2dcf98fd2c17aabb57eb7bbb27200552f29c247&ext=.gif)
New UHSS Grades from Hoesch Hohenlimburg
12/29/2009 - Hoesch Hohenlimburg’s family of micro-alloyed, fine-grained structural steels adds four new members: HSM 550 HD, HSM 600 HD, HSM 650 HD, and HSM 700 HD. The HD grades are used by automakers and their suppliers to make complex precision-blanked and stamped parts.
Hoesch Hohenlimburg’s family of micro-alloyed, fine-grained structural steels has four new members: HSM 550 HD, HSM 600 HD, HSM 650 HD, and HSM 700 HD. (HSM stands for Hoesch Special structural steels Micro-alloyed; HD stands for high-ductility; and the numbers indicate minimum yield strength in MPa.)
The company says its HD grades are used by auto manufacturers and their suppliers to make complex precision-blanked and stamped parts such as seatback adjusters. The high strength of the materials allows components to be designed with reduced wall thickness, according to Hoesch Hohenlimburg, and heat treatment is not needed to increase strength.
The HD grades from Hoesch Hohenlimburg are single-phase, unlike most other steel materials with good formability and yield strengths of 500 to 700 MPa, which are multi-phase, according to the company. The patented materials owe their “superior” forming properties to their virtually pearlite-free fine-grained microstructure, says Hoesch Hohenlimburg, and their carbon content is significantly lower than standard grades. The associated loss of strength is offset by micro-alloying elements such as molybdenum, niobium, and titanium.
The company says that these elements develop their potential during the thermo-mechanical rolling of the steels in the narrow strip mill at Hoesch Hohenlimburg GmbH. The company explains that precise temperature control in the walking beam furnace and finely balanced rolling forces in the roughing stand and finishing trains of the narrow strip mill initiate a process that causes the micro-alloying elements to form tiny precipitations measuring millionths of a millimeter, giving the HD grades the required strength.
Hoesch Hohenlimburg supplies the HD grades as Hohenlimburg narrow strip—i.e., hot-rolled strip in widths of up to 685 mm and thicknesses of 1.5 to 16 mm—that the company claims offers thickness tolerances comparable to cold strip and optimum surface quality.
