Diamond Wire Rod Composition for 5000 MPa Strength and Drawability

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Solution Overview

Problem

Current wire rods are unable to meet the high requirements for producing 5000 MPa-grade diamond wires in terms of diameter and continuous wire mileage, lacking the necessary purity, structural uniformity, and mechanical properties.

Innovation Solution

A wire rod production method involving vacuum melting, electroslag or vacuum arc remelting, billet making, high-speed wire rolling, and controlled cooling to achieve a specific chemical composition and microstructure, including 1.01% to 1.10% C, 0.15% to 0.40% Si, 0.30% to 0.60% Mn, and 0.01% to 0.40% Cr, with optional B and V additions, to enhance strength and prevent inclusions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If conventional wire rod production methods are used, then production cost and process simplicity are maintained, but the wire rod cannot achieve the required purity, structural uniformity, and tensile strength for 5000 MPa-grade diamond wires

Engineering Contradiction:
Improvetensile strengthVSAvoidproduction process complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The production process is divided into multiple distinct stages: vacuum melting, electroslag remelting, vacuum arc remelting, billet making, high-speed wire rolling, and controlled cooling. Each stage addresses specific requirements for purity and structure, with vacuum melting removing impurities, remelting processes refining composition, and controlled cooling developing desired microstructure. This segmentation enables achieving 5000 MPa tensile strength through systematic control of each production phase.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention employs precise control of chemical composition parameters (C: 1.01-1.10%, Si: 0.15-0.40%, Mn: 0.30-0.60%, Cr: 0.01-0.40%, B: 0.0005-0.0020%, V: 0.01-0.09%) and process parameters (vacuum level, remelting speed, rolling temperature, cooling rate) to transform conventional wire rod properties. These parameter changes enable the wire rod to achieve ultra-high tensile strength of 5000 MPa while maintaining drawing properties.

Inventive Principle:
Principle #35Parameter changes

2Loss of substance

If wire rod diameter is reduced to produce thinner diamond wires, then material loss during cutting is reduced, but the wire rod must maintain higher strength and purity which current production methods cannot achieve

Engineering Contradiction:
Improvematerial loss during cuttingVSAvoidwire rod purity and structural uniformity
Core Design Contradiction:
Loss of substanceVSManufacturing precision

Solution Approach 1:

The invention uses vacuum melting and electroslag remelting in protected atmospheres to prevent oxidation and contamination during production. The vacuum environment (10^-2 to 10^-4 Pa) and inert gas shielding ensure ultra-high purity of the wire rod, enabling production of thinner diameters with maintained strength. This inert environment control is critical for achieving the required manufacturing precision in ultra-fine wire rods.

Inventive Principle:
Principle #39Inert atmosphere (Inert environment)

Solution Approach 2:

The multi-stage remelting processes (electroslog remelting followed by vacuum arc remelting) systematically extract and remove impurities from the molten steel. Each remelting cycle separates unwanted elements and inclusions, concentrating pure metal. This extraction process achieves the ultra-high purity required for thin wire rod production, enabling reduced material loss in cutting applications.

Inventive Principle:
Principle #2Taking out (Extraction)

3Strength

If the wire rod is strengthened to achieve 5000 MPa tensile strength, then diamond wire strength is improved, but the drawing properties may deteriorate making deep drawing difficult

Engineering Contradiction:
Improvetensile strengthVSAvoiddrawing properties
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The invention utilizes controlled phase transitions during cooling to develop a microstructure that balances strength and ductility. The controlled cooling rate (10-100°C/s) transforms austenite into a fine pearlitic or bainitic structure, achieving 5000 MPa tensile strength while maintaining adequate elongation. This phase transition control enables the wire rod to possess both ultra-high strength and sufficient drawing properties for deep drawing into diamond wires.

Inventive Principle:
Principle #36Phase transitions

Solution Approach 2:

The wire rod employs a composite microstructure consisting of fine-grained ferrite, pearlite, and controlled carbide distributions created through the specific composition and cooling process. This composite structure at the micro-scale provides both the 5000 MPa strength requirement and the ductility needed for drawing. The combination of multiple phases and strengthening mechanisms (solid solution, grain boundary, and precipitation strengthening) resolves the contradiction between strength and formability.

Inventive Principle:
Principle #40Composite materials

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The method produces wire rods with high purity, structural uniformity, and enhanced tensile strength, suitable for drawing diamond wires with diameters of 40 μm to 46 μm and a wire breakage rate less than 2 times/thousand kilometers, meeting the market demands for high-strength and low-breakage diamond wires.

Implementation Method 1

melting molten steel by adopting a vacuum melting furnace in an atmosphere with a pressure in the furnace below 10 Pa

Methodology Applied
Scientific EffectVacuum: Vacuum

Implementation Method 2

processing the steel ingot by adopting either or both of electroslag remelting and vacuum arc remelting

Methodology Applied
Scientific EffectElectroslog remelting:

Implementation Method 3

a remelting speed of the vacuum arc remelting is 3.0 kg/min to 3.5 kg/min

Methodology Applied
Scientific EffectVacuum arc remelting:

Implementation Method 4

rolling the steel billet into the wire rod, with an initial rolling temperature of 1030° C. to 1060° C., and a final rolling temperature of 950° C. to 1020° C.

Methodology Applied
Scientific EffectHigh-speed wire rolling:

Implementation Method 5

cooling: carrying out temperature-controlled cooling on the wire rod on a Stelmor cooling line, starting 1st to 4th fans with air quantities of 80% to 100%

Methodology Applied
Scientific EffectTemperature-controlled cooling: Cooling

Data Source

PatentUS20230416865A1Wire rod for 5000 mpa-grade diamond wire and production method therefor
Publication Date: 2023.12.28 INST OF RES OF IRON & STEEL JIANGSU PROVINCE SHA-STEEL CO LTD (CN) ZHANGJIAGANG RONGSHENG SPECIAL STEEL CO LTD & JIANGSU SHAGANG GRP CO LTD

AI summary

A wire rod for a 5000 MPa-grade diamond wire and a production method are provided. The wire rod includes the following chemical components: 1.01% to 1.1% of carbon, 0.15% to 0.4% of silicon, 0.3% to 0.6% of manganese, 0.01% to 0.4% of chromium, 0.0005% to 0.002% of boron and/or 0.01% to 0.09% of vanadium; and the balance of iron and impurities. The production method includes vacuum melting, electroslag remelting and/or vacuum consumable melting, grinding after cogging/forging, high-speed wire rolling and cooling, and cogging at 1030° C. to 1060° C. The wire rod, with structural uniformity and tensile strength of more than or equal to 1320 MPa, can be configured to prepare 5000 MPa-grade steel wires with a diameter of 40 μm to 46 μm.