Non-scaling heat-treatable steel and method for producing a non-scaling component from said steel

Abstract

A non-scaling heat-treatable steel with particular suitability for producing hardened or die-hardened components is disclosed, characterized by the following chemical composition in % by weight: C 0.04-0.50; Mn 0.5-6.0; Al 0.5-3.0; Si 0.05-3.0; Cr 0.05-3.0; Ni less than 3.0; Cu less than 3.0; Ti 0.0104-0.050; B 0.0015-40.0040; P less than 0.10; S less than 0.05; N less than 0.020; remainder iron and unavoidable impurities. Further disclosed is a method for producing a non-scaling hardened component from the steel and a method for producing a hot strip from a steel.

Claims

1. A non-scaling heat treatable steel, comprising a following chemical composition in weight %: C: 0.04-0.50 Mn: 0.5-6.0 Al: 0.5 to 3.0 Si: 0.05-3.0 Cr: 0.05-3.0 Ni: less than 3.0 Cu: >1.2-<3.0 Ti: 0.010-0.050 B: 0.0015-0.0040 P: less than 0.10 S: less than 0.05 N: less than 0.020 remainder iron and unavoidable impurities, wherein a total content of aluminum, silicon and chromium is at least 3 weight % to inhibit scaling, wherein said non-scaling heat treatable steel has no coating for oxidation or scaling protection prior to heating or forming.

2. The non-scaling heat treatable steel of claim 1, wherein Mn+Ni+Cu1 weight %.

3. The non-scaling heat treatable steel of claim 1, wherein Mn+Ni+Cu2 weight %.

4. The non-scaling heat treatable steel of claim 1, wherein Mn+Ni+Cu3 weight %.

Description

BRIEF DESCRIPTION OF THE DRAWING

(1) The sole FIGURE in the appendix schematically shows a method sequence according to the invention for the condition casting speed=rolling speed.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

(2) The casting method with a horizontal strip casting system 1 is located upstream of the hot rolling process, and is composed of a rotating conveyor belt 2 and two deflector rolls 3, 3. A lateral sealing 4 can also be seen which prevents that the applied melt 5 flows off the conveyor belt to the right hand or left hand side. The melt 5 is transported to the strip casting system 1 by means of a pan 6 and flows through an opening 7 provided in the bottom of the pan into a supply container 8. This supply container 8 is constructed in the manner of an overflow.

(3) Not shown are the devices for intensive cooling of the bottom of the upper tower of the conveyor belt 2 and the complete housing of the strip casting system 1 with corresponding inert gas atmosphere.

(4) For temperature compensation and tension reduction a homogenization zone 10 adjoins the strip casting system 1. The homogenization zone includes a heat insulating housing 11 and a here not shown roller table.

(5) The first stand 12 following thereafter is either configured only as pure drive unit optionally with a small pass or a roller unit with a predetermined pass.

(6) Following is an intermediate heating, here preferably as inductive heating for example configured in the form of a coil 13. The actual hot forming occurs in the subsequent stand array 14, wherein the first three stands 15, 15, 5 cause the actual pass reduction, while the last stand 16 is configured as smoothening stand.

(7) Following the last pass is a cooling zone 17, in which the hot strip is cooled down to coiling temperature.

(8) Between the end of the cooling distance 17 and the coiling 19, 19 a scissor 20 is arranged. This scissor 20 has the purpose to separate the hot strip 18 transversely as soon as the one of the two coils 19, 19 is fully wound up. The beginning of the following hot strip 18 is then guided onto the second released coil 19, 19. This ensures that the tension on the strip is maintained over the entire strip length. This is particularly important when producing thin hot strips.

(9) Not shown in the FIGURE are the system components for cold rolling of the hot strip.