Lead-free patenting process and equipment

Patent metadata

Field	Value
Publication number	US-11299795-B2
Application number	US-201816473875-A
Country	US
Kind code	B2
Filing date	Jan 9, 2018
Priority date	Jan 12, 2017
Publication date	Apr 12, 2022
Grant date	Apr 12, 2022

Abstract

The controlled cooling of previously heated and substantially straight steel wires of diameter more than 3.5 mm to a predetermined temperature including the steps: guiding the wires along individual paths through first coolant bath having bath liquid of water and a stabilizing additive, the bath liquid and the wires create a steam film around each wire along individual paths; directing an impinging liquid immersed inside first coolant bath towards the wires over a length along individual paths to cool down the wires, the impinging liquid decreases the thickness of the steam film or destabilizes the steam film, increasing speed of cooling over the length along individual paths; guiding the wires along individual paths out of the first coolant bath to be cooled down in air; after the further cooling, guiding the wires along individual paths through second coolant bath.

First claim

The invention claimed is:

1. A method of controlled cooling of one or multiple previously heated and substantially straight steel wire/wires to a predetermined temperature range, the previously heated and substantially straight steel wires having a diameter which is more than 3.5 mm and less than 20 mm, the method comprises the steps of:
a) guiding the previously heated and substantially straight steel wire/wires along individual path/paths through one or multiple first coolant bath/baths, the first coolant bath/baths comprises a bath liquid, wherein the bath liquid comprises water and a stabilizing additive, wherein the bath liquid and the multiple previously heated and substantially straight steel wires create a steam film around each steel wire itself along each individual path;
b) directing an impinging liquid immersed inside the first coolant bath/baths towards the previously heated and substantially straight steel wire/wires over a certain length L along individual path/paths, to cool down the previously heated and substantially straight steel wire/wires, wherein the impinging liquid decreases the thickness of the steam film or destabilizes the steam film, thereby increasing the speed of cooling over the length L along individual path/paths,
c) guiding the previously heated and substantially straight steel wire/wires along individual path/paths out of the first coolant bath/baths to be further cooled down in air,
d) after the further cooling in air, guiding the previously heated, substantially straight steel wire/wires along individual path/paths through one or multiple second coolant bath/baths,

wherein the substantially straight steel wire/wires are subjected to a cooling transformation from austenite to pearlite.

2. The method according to claim 1 , wherein the impinging liquid is immersed below each of the previously heated and substantially straight steel wire itself along each individual path; or wherein the impinging liquid is immersed partially below some of the multiple previously heated and substantially straight steel wires along their individual paths.

3. The method according to claim 1 , wherein the length of the first coolant bath and/or of the second coolant bath/baths are adjustable.

4. The method according to claim 1 , wherein the first coolant bath is provided with partitioning walls separating steel wires in the first coolant bath along the length of the steel wires along which the steam film around the steel wires is affected by the impinging liquid, such that impinging liquids onto a first steel wire do not affect the steam film around a second steel wire.

5. The method according to claim 1 , wherein the intensity of the impinging liquids is individually set and/or controlled for each individual steel wire or for subsets of the plurality of steel wires.

6. The method according to claim 1 , wherein the first coolant bath(s) has/have a fixed length.

7. The method according to claim 1 , wherein the impinging liquid has the same chemical composition as the bath liquid of the first coolant bath.

8. The method according to claim 1 , wherein the impinging liquids are continuously recirculated and controlled by a flow rate control system.

9. The method according to claim 8 , wherein one or a plurality of sensors are provided to measure the magnetic response of one or more than one of the steel wires; and to provide feedback to adapt in a closed loop control the impinging liquids in the first coolant baths.

10. The method according to claim 1 , wherein the cooling transformation from austenite to pearlite starts substantially when the previously heated and substantially straight steel wire is cooled down in air between the first coolant bath and the second coolant bath.

11. The method according to claim 1 , wherein each of the steel wire is previously heated above austenitizing temperature and cooled down to a predetermined temperature between 400° C. and 650° C.

Assignees

• Bekaert Sa Nv

Inventors

• Mesplont Christophe
• Bruggeman Tim
• Beyens Franky
• Holvoet Jan
• Lapeire Gregory

Classifications

• C21D2211/001

  Austenite · CPC title

• C21D9/5732 Primary

  of wires; of rods · CPC title

• C21D1/64 Primary

  with circulating liquids · CPC title

• C21D9/54

  Furnaces for treating strips or wire · CPC title

• C21D1/63 Primary

  for bath quenching · CPC title