Process for the heat treatment of steel strips

Patent metadata

Field	Value
Publication number	US-9322598-B2
Application number	US-16264107-A
Country	US
Kind code	B2
Filing date	Jan 11, 2007
Priority date	Feb 3, 2006
Publication date	Apr 26, 2016
Grant date	Apr 26, 2016

Abstract

The invention provides a process for the heat treatment of steel products, in particular of steel strips or sheets, in which the product is brought from a starting temperature to a target temperature in a booster zone having at least one burner; the burner is operated with a fuel, in particular a fuel gas, and an oxygen-containing gas which contains more than 21% oxygen; and the product is brought into direct contact with the flame generated by the burner, the air ratio λ within the flame being set as a function of the starting temperature and/or the target temperature.

First claim

What is claimed is:

1. A method for the heat treatment of steel products to be treated in a furnace, wherein a steel product in a booster zone having at least one burner is brought from a starting temperature to a target temperature, the at least one burner operating with a fuel and an oxygen-containing gas, the oxygen-containing gas including more than 21% oxygen and the steel product directly contacting a flame generated by the at least one burner, the method comprising:
moving the steel product through the booster zone upstream of the furnace in a conveying direction to the furnace,
providing the flame in a direction transverse to the conveying direction and directly contacting the steel product with the flame,
surrounding the steel product over its entire periphery with the flame provided transversely to the conveying direction, and
providing an air ratio λ within the flame set as a function of the starting temperature and/or the target temperature in the booster zone.

2. The method according to claim 1 further comprising:
providing additional booster zones in which the steel product in each of said additional booster zones is brought from a starting temperature to a target temperature, and
setting the air ratio λ as a function of the respective starting temperature and/or the respective target temperature in each of the additional booster zones.

3. The method according to claim 2 , further comprising:
providing at least one additional burner operated with fuel and a gas containing more than 21% oxygen for each one of said additional booster zones,
heating each one of said additional booster zones with a corresponding one of, said additional burners, and
contacting the steel product directly with the flame generated by the at least one additional burner.

4. The method according to claim 1 , further comprising
acting on the steel product with a heat flux density of 300 to 1000 kW/m2 in the booster zone.

5. The method according to claim 1 , further comprising
influencing the target temperature in the booster zone using a flame geometry of the at least one burner.

6. The method according to claim 1 , further comprising:
heating the steel product to a first target temperature of 300°C. to 400°C. in the booster zone, and
heating the steel product from the first target temperature to a temperature of from 600° C. to 900° C. in at least one further treatment zone.

7. The method according to claim 1 , further comprising:
heating the steel product to a first target temperature of from 500° C. to 600° C. in a first treatment zone, and
heating the steel product from the first target temperature to a temperature of from 600° C. to 900° C. in the booster zone.

8. The method according to claim 1 , further comprising
subjecting the steel product to a coating/galvanization process.

9. The method according to claim 1 , further comprising:
exposing the steel product to a reducing atmosphere, and
providing the steel product to the booster zone for heating to the target temperature.

Assignees

• Eichelkraut Herbert
• Heiler Hans-Joachim
• Högner Werner
• Jindra Fred
• Paul Rainhard
• Ritzén Ola
• Linde Ag

Inventors

• Eichelkraut Herbert
• Heiler Hans-Joachim
• Högner Werner
• Jindra Fred
• Paul Rainhard
• Ritzén Ola

Classifications

• C21D11/00

  Process control or regulation for heat treatments · CPC title

• C21D9/56 Primary

  Continuous furnaces for strip or wire · CPC title

• F27D19/00 Primary

  Arrangements of controlling devices · CPC title

• C21D9/561

  with a controlled atmosphere or vacuum · CPC title

• F27D99/0033

  using burners · CPC title