Metal sheet with tailored properties
Moving metal strips can be heat treated with any number or combination of dimensionally variable tempers across widths, lengths, or thicknesses of a metal strip. To provide dimensionally variable heat treatment, an apparatus can include one or more heating units suitable to increase the temperature of a metal strip moving proximate the apparatus to a heat treatment temperature. The apparatus can also include one or more cooling units positioned near the heating units to absorb heat and cool the metal strip to minimize the amount of heat transferred from a first region of the metal strip that is to be treated to a second region of the metal strip that is not to be treated.
1. A method for variably heat treating a metal article across a dimension of the metal article, the method comprising:
moving a metal article along a processing line through a dimensionally variable heat treatment apparatus having a heating unit and a cooling unit positioned on opposite sides of a separation plane, wherein the metal article is continuously moving along the processing line in a processing direction at a strip rate;
heating a first portion of the moving metal article by the heating unit, wherein heating the first portion includes raising a strip temperature of the first portion of the moving metal article at or above a heat treatment temperature for a duration;
cooling the moving metal article by the cooling unit, wherein cooling the moving metal article includes removing heat from the moving metal article adjacent the first portion sufficiently to maintain a temperature of a second portion of the moving metal article below the heat treatment temperature, wherein the second portion of the metal article is located opposite the separation plane from the first portion;
detecting a vertical and lateral position of the heating unit and the cooling unit as the metal article moves along the processing line;
adjusting a vertical and lateral position of the heating unit and the cooling unit along the processing line while the metal article is moving at the strip rate; and
adjusting an intensity of the heating unit and the cooling unit based on the vertical and lateral position of the heating unit or the cooling unit along the processing line.
2. The method of claim 1 , further comprising:
cooling the first portion of the moving metal article after heating the first portion of the moving metal article for the duration.
3. The method of claim 1 , further comprising laterally adjusting the dimensionally variable heat treatment apparatus to move the separation plane with respect to the moving metal article.
4. The method of claim 3 , further comprising determining a longitudinal position of the dimensionally variable heat treatment apparatus along the moving metal article, wherein laterally adjusting the dimensionally variable heat treatment apparatus includes moving the separation plane with respect to the moving metal article as a function of the longitudinal position of the dimensionally variable heat treatment apparatus.
5. The method of claim 1 , further comprising vertically adjusting the dimensionally variable heat treatment apparatus to move the separation plane with respect to the moving metal article.
6. The method of claim 1 , wherein the separation plane is parallel the moving metal article, wherein heating the first portion of the moving metal article includes heating one of a top and a bottom of the moving metal article, and wherein cooling the moving metal article includes removing heat from another of the top and the bottom of the moving metal article.
7. The method of claim 1 , wherein the separation plane is parallel a longitudinal axis of the moving metal article and perpendicular a top surface of the moving metal article, wherein the dimensionally variable heat treatment apparatus further includes an additional heating unit and an additional cooling unit each positioned on opposite sides of the separation plane and both positioned opposite the moving metal article from the heating unit and the cooling unit, wherein heating the first portion of the moving metal article includes heating the top surface and a bottom surface of the moving metal article proximate the first portion, and wherein cooling the moving metal article includes cooling the top surface and the bottom surface of the moving metal article proximate the second portion.
8. The method of claim 1 , further comprising heating the metal article in an initial heat treatment step.
9. The method of claim 1 , further comprising heating the metal article in a final heat treatment step.
10. The method of claim 1 , wherein the method comprises simultaneously heating the first portion of the moving metal article by the heating unit and cooling the second portion of the moving metal article.