Method for determining the stamping quality of profiled bar material

A method for determining a stamping quality of bar material having a ribbed or recessed profile, which is advanced in a rolling train that includes a rolling stand (3) that carries out a shaping process by means of stamping rollers, the method comprising:

• a) upstream of the rolling stand (3), an initial speed VA of a starting product (1) to be shaped by the rolling stand (3) is determined and, an initial diameter DA or an initial cross-sectional area FA are determined contactlessly,
• b) after the rolling stand (3), a final speed VE of an end product (2) is measured and a diameter DE or a cross-sectional area FE of a virtual enveloping shell for the end product (2) is/are determined contactlessly, the diameter DE or cross-sectional area FE of the virtual enveloping shell being a maximum or average diameter or cross-sectional area of the ribbed or recessed profile
• c) a diameter DN of a virtual, round end product is determined contactlessly as
• DN=square root of (DA2×VA/VE)
• or
• an average cross-sectional area FNE of the end product (2) is determined contactlessly as
• FNE=FA×VA/VE,
• d1) a characteristic stamping variable PKG is calculated on a basis of DE and DN or on a basis of FE and FNE, wherein the characteristic stamping variable PKG is calculated as a difference between or a ratio of DE and DN or as the difference between, or the ratio of, FE and FNE, or
• d2) values determined and calculated in steps a), b) and c) are used for calculating variables derived from them, the derived variables being:
• i) an initial volume or an initial weight per unit of length of the starting product (1),
• ii) a volume or a weight of the virtual enveloping shell per unit of length
• iii) a volume of the end product (2) per unit of length or a weight of this volume of the end product (2), and
• iv) the characteristic stamping variable PKG is calculated as the difference between or the ratio of the volume of the virtual enveloping shell per unit of length and the volume of the end product (2) per unit of length, and/or the difference between the or the ratio of the weight of the virtual enveloping shell per unit of length and the weight of the end product (2) per unit of length, and
• e) the characteristic stamping variable PKG is compared with a pre-set setpoint value PKGset, wherein PKGset represents a desired stamping quality.