Claims
- 1. A method for in-line heat treating of steel stock hot rolled in a rolling mill, comprising the steps, conducted in-line with the rolling mill, of:
a. cutting the rolled stock into pieces of predetermined length; b. quenching the pieces of hot rolled stock in a quenching box; c. in preparation for tempering of the quenched stock, preparing at least one layer of a predetermined number of cut pieces of stock in a layers preparation zone, with use of a layers preparation system, wherein the number of cut pieces of stock per layer depends on the section of the rolled stock; d. tempering the prepared layer(s) of stock arranged in one or more level(s) in an on-line annealing furnace for controlled cooling, holding or heating of the layer(s) of stock; e. separating and discharging the layer(s) from the one or more level(s) into individual pieces of quenched and tempered stock with use of a separating and discharging device, and f. cooling the quenched and tempered stock in a cooling bed.
- 2. A method according to claim 1, wherein the pieces of hot rolled stock coming from the quenching box have a temperature in the range 50 to 150° C.
- 3 A method according to claim 1, wherein tempering takes place while holding the layers of stock at a temperature in the range 500 to 700° C. for a time about 60 minutes to about 120 minutes.
- 4. A method according to claim 1, further comprising the step of induction heating the rolled and quenched stock in-line before preparing layers to help the following tempering of the rolled stock in the annealing furnace.
- 5. A method according to claim 1, wherein cooling in the quenching box is started from a temperature of about 800° C.
- 6. A method according to claim 1, further comprising
a subsequent in-line finishing step selected from the group consisting of final cooling in a water box, shotblasting, cutting to final form, and packaging.
- 7. A method according to claim 1, wherein the cooling bed is provided with a protective atmosphere.
- 8. A method according to claim 1, wherein the number of levels in the on-line annealing furnace is two or more.
- 9. A method according to claim 1, wherein
said layers preparation system in said layers preparation zone is positioned inside the on-line annealing furnace, and said separating and discharging device is positioned inside the on-line annealing furnace.
- 10. A method according to claim 1, wherein said layers preparation system in said layers preparation zone is positioned outside the on-line annealing furnace, and
said separating and discharging device is positioned outside the on-line annealing furnace.
Parent Case Info
[0001] This application is a divisional of prior application Ser. No. 09/315,848 filed May 21, 1999.
Divisions (1)
|
Number |
Date |
Country |
Parent |
09315848 |
May 1999 |
US |
Child |
09976209 |
Oct 2001 |
US |