The 40Cr seamless steel tube is an alloy tube 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 Celsius, tempered at 520 degrees Celsius: 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 further categorized into 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-roller oblique rolling, continuous rolling, or extrusion → Tube removal → Size (or reduce size) → Cooling → Bloom → Straightening → Hydrostatic test (or flaw detection) → Marking → Storage.

Cold Drawn (rolled) Seamless Steel Tubes: Round billet → Heating → Piercing → Heading → Annealing → Pickling → Oiling (copper plating) → Multi-pass cold drawing (cold rolling) → Bloom → Heat treatment → Straightening → Hydrostatic test (NDT) → 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 tube cold-rolled blank softening processing specification: Temperature 740~760°C, holding time 4~6h, cooling rate 50~100°C/h, furnace cooling to ≤600°C, then air-cooled. Hardness ≤217HBS before treatment, ≤163HBS after treatment.

Iron屑 Protective Swing Ghost Specifications

(670±10)℃×2h, furnace heating, (710±10)℃×2h, furnace cooling, (670±10)℃×2h, furnace heating, (710±10)℃×2h, followed by furnace cooling, (670±10)℃×2h, furnace heating, (710±10)℃×2h, furnace cooling, total of 3 cycles, then cooled down to 550℃, air-cooled after removal. Hardness after treatment: 153HBS.

Specification for tempering treatment of seamless steel tubes: Quenching temperature 850±10°C, oil-cooled; tempering temperature 520±10°C, water or oil cooling.

Application Examples

1. Suitable for stretch film and shaping molds.

2. Cold extrusion punches, heavy-duty cold heading punches, punches for 10-25mm medium-thick steel plate holes, and small punches with diameters Φ5-6mm.

3. Suitable for medium and small die sets, as well as small, high-life cold heading tools.

4. Manganese slag protective oscillating fire specifications are suitable for cold extrusion forming tools.

5. Powder Metallurgy Molding Presses

Formula for weight per meter: 0.02466 * wall thickness * (outer diameter - wall thickness)