Precision Seamless Steel Tubes

The 40Cr seamless steel pipe is an alloy pipe made of 40Cr.

Overview

Chemical Composition and Mechanical Properties: Composition: Silicon 0.17～0.37%, Manganese 0.5～0.8, Chromium 0.8～1.1%

Tempering Treatment: Sample Diameter: 25mm, quenched in oil at 850 degrees, tempered at 520 degrees: Tensile strength 1000 MPa, yield strength 800 MPa, elongation 9%, reduction of area 45%, impact toughness 588.3 kJ/m².

Due to the different manufacturing processes of 40Cr seamless steel tubes, they are categorized into two types: hot rolled (extruded) seamless steel tubes and cold drawn (rolled) seamless steel tubes. The cold drawn (rolled) tubes are further divided into round tubes and shaped tubes.

Process Flow

Hot rolled (extruded seamless steel tube): round billet → heating → piercing → three-roll oblique rolling, continuous rolling, or extrusion → pipe removal → sizing (or reduction) → cooling → bloom → straightening → hydrostatic testing (or flaw detection) → marking → storage.

Cold drawn (rolled) seamless steel tube: Round billet → Heating → Piercing → Heading → Annealing → Pickling → Oiling (copper plating) → Multi-pass cold drawing (cold rolling) → Bloom → Heat treatment → Straightening → Hydrostatic test (detection) → Marking → Storage.

Alloy Steel: a. Low-alloy steel (total alloy content ≤ 5%) b. Medium-alloy steel (total alloy content > 5% ~ 10%) c. High-alloy steel (total alloy content > 10%)

Normalizing specification: Normalizing temperature 850-870°C, hardness 179-229HBS after normalizing.

40cr Seamless Steel Pipe Cold-rolled Billet Softening Treatment Specification: Temperature 740~760°C, holding time 4~6h, cooling rate 50~100°C/h, furnace-cooled to ≤600°C, then air-cooled. Hardness ≤217HBS before treatment, ≤163HBS after treatment.

Iron chip protective swinging ghost specifications

(670±10)℃×2h, furnace升温, (710±10)℃×2h, furnace降温, (670±10)℃×2h, furnace升温, (710±10)℃×2h, further furnace降温, (670±10)℃×2h, furnace升温, (710±10)℃×2h, furnace降温, total of 3 cycles, then cool to 550℃, air cool after removal. Hardness after treatment: 153HBS.

Seamless steel tube tempering specifications: Quenching temperature 850±10°C, oil cooled; tempering temperature 520±10°C, water or oil cooled.

Application Examples

1. Suitable for stretch film and molding.

2. Cold forming punches, heavy-duty cold heading punches, punches for medium-thick steel plates 10-25mm thick, small punches with diameters of Φ5-6mm.

3. Suitable for medium and small-sized punches, as well as small, high-life cold punch shearing tools.

4. Manganese iron scale protection swinging fire regulations can be used for cold extrusion forming tools.

5. Powder Metallurgy Dies

Calculation formula for weight per meter: 0.02466 x wall thickness x (outer diameter - wall thickness)