Deep underground, on longwall shearers and roadheaders, one component takes the most brutal punishment every day — the Cutting pick. As the "tooth" of mining machinery that directly contacts coal and rock, the performance of the cutting pick directly affects mining efficiency, equipment energy consumption, operational safety, and even the entire mine's operating cost.

Small as it is, the cutting pick is one of the highest-consumption and most technically sophisticated basic components in mining. This article covers cutting picks in seven parts: functional positioning, product series, material selection, forming and heat treatment, carbide tip and connection technology, quality control systems, and future trends.

Function: The "Tooth" of Mining Machinery

The cutting pick is a cutting tool mounted on shearer drums, roadheader cutting heads, or rotary drilling rig buckets. Its core function is simple: under mechanical drive, through rotation or reciprocating motion, it directly contacts coal and rock. Using the high hardness and wear resistance of its carbide tip, it breaks and peels coal and rock from the parent body.

A cutting pick works in an extremely harsh environment:

• High impact loads — single-tooth impact loads can reach several tons.

• Severe abrasion — hard minerals like quartz and pyrite in coal and rock grind against the pick surface.

• High temperatures — frictional heat from high-speed cutting can raise tip temperature to hundreds of degrees Celsius.

• Corrosion — humid underground conditions and acidic water can corrode metal components.

Therefore, a good cutting pick must achieve a delicate balance between strength, hardness, toughness, wear resistance, and impact resistance.

Product Series: Adapting to Different Mining Scenarios

Cutting picks have formed a complete series product system that can be selected based on equipment and working conditions.

Shearer picks are mounted on the drum of a longwall shearer. They rotate with the drum to cut the coal face. Features include long bodies to handle high torque, large shank diameters (typically 30–38 mm) to withstand bending moments, and various tip shapes (conical, spherical, or wedge-shaped) based on coal hardness. A typical shearer drum carries 100–200 picks. Failure of a single pick can disrupt production.

Roadheader picks are mounted on the cutting head of boom-type or full-face roadheaders. They must handle everything from soft coal to hard rock. Features include richer tooth designs (point-attack and radial types), higher wear resistance requirements for carbide tips, and reinforced bodies through stricter heat treatment and surface strengthening.

Rotary drilling picks are used on drilling buckets of rotary drilling rigs — mainly in foundation engineering and shoring. They encounter soil, gravel, cobbles, and weathered rock. Features include shorter bodies for tight spaces, sharply pointed carbide tips for penetration in loose ground, and a holder-and-sleeve system for quick field replacement.

Other specialized picks include milling picks for road planers and trenching picks for trenchers — forming a complete product matrix covering multiple types of construction machinery.

Material Selection: The Foundation of Performance

Cutting pick performance starts with material selection. A pick has two main parts — the steel body and the carbide tip — each with different material requirements.

The steel body must take impact loads, transmit torque, and resist chip erosion. Therefore, it needs high tensile strength (typically 900–1100 MPa or higher), high impact toughness (AKV of 40–60 J or higher), and appropriate hardness — wear-resistant but not brittle.

35CrMo and 42CrMo are the two most common high-quality alloy steels for pick bodies. Typical properties:

42CrMo has higher carbon and molybdenum content, better hardenability, and higher strength — suitable for heavy-duty picks and hard rock. 35CrMo is widely used in conventional conditions due to its good all-around performance and cost advantage.

The carbide tip is the core element that directly breaks coal and rock. It is made of cemented carbide, with YG11C as the typical grade.

YG11C is a tungsten carbide-cobalt (WC-Co) carbide. "YG" stands for tungsten-cobalt. "11" indicates about 11% cobalt by weight. "C" indicates coarse tungsten carbide grains, which improve impact resistance.

Typical properties of YG11C:

This material combination gives the tip high hardness while maintaining good impact toughness — resisting chipping under high impact loads.

Forming and Heat Treatment: From Steel to Precision Component

The manufacturing process of the pick body has a decisive impact on final performance. Modern high-end picks generally use "cold forging + vacuum heat treatment."

Large cold forging press forming — Traditional pick body manufacturing used machining — "cutting" the body shape from bar stock. That process had clear defects: metal flow lines were cut, loose areas were exposed, and fatigue strength was low.

Large cold forging press forming changed this completely. The process places heated high-quality steel into a precision mold and extrudes it in one stroke under thousands of tons of pressure. Advantages include:

• Continuous, complete metal flow lines — like tree rings, significantly improving fatigue strength.

• Dense structure — high pressure eliminates casting defects and internal porosity.

• High dimensional accuracy — the mold ensures consistent external dimensions, reducing subsequent machining.

• High material utilization — nearly non-cutting, greatly reducing material waste.

Vacuum heat treatment — Heat treatment is the key step that gives the body its final mechanical properties. Traditional salt bath or atmosphere heat treatment often causes surface oxidation and decarburization, affecting surface hardness and fatigue life.

Vacuum heat treatment heats and cools in a vacuum environment. Advantages include:

• No oxidation, no decarburization — the vacuum prevents oxygen from reacting with the steel surface.

• Smooth surface — no need for subsequent sandblasting or pickling.

• Uniform hardness — vacuum heating is more uniform than traditional methods, with less hardness variation.

• Environmentally friendly — no salt bath waste liquid or atmosphere exhaust.

After vacuum heat treatment, pick body hardness is stably controlled between 40–45 HRC. This range is the optimum verified by extensive practice:

• Below 40 HRC: insufficient wear resistance — body wears too quickly, causing tip loss.

• Above 45 HRC: reduced toughness — prone to fracture under impact loads.

At the same time, vacuum heat treatment fully preserves the body's impact toughness, ensuring it does not crack under heavy loads.

Tip-to-Body Connection: Weld and Wear Layer Working Together

The quality of the connection between the carbide tip and the steel body is critical to whether a pick will experience "tip loss" failure.

Brazing is used to join the tip and body. During brazing, filler metal (typically copper-based or silver-based) is placed between the tip and the socket wall, heated until it melts, and then cooled to form a strong metallurgical bond.

Key quality control points include brazing temperature (too high damages the carbide, too low prevents filler flow), holding time (ensures complete filling), and cooling rate (too fast causes thermal stress cracks, too slow affects productivity).

Around the weld, the pick has a high-hardness wear-resistant layer with hardness reaching about 60 HRC — much higher than the body's 40–45 HRC.

The wear layer has critical functions:

• Protects the weld from direct abrasion by rock chips — preventing premature weld exposure and failure.

• Delays body wear — after the tip gradually wears, the wear layer acts as a "backup cutting edge," extending overall pick life.

• Prevents tip loss — the wear layer forms a "cradle" around the tip root, enhancing resistance to impact-induced loss.

The wear layer is typically applied by hardfacing or cladding using tungsten carbide particle-reinforced alloy powder. Field data shows that picks with a high-quality wear layer last 30–50% longer than picks without one.

Weld fullness is an important indicator of brazing quality. A full weld means the filler metal has completely filled the gap between tip and body, with no voids, slag inclusions, or lack of fusion. Inspection combines visual examination and penetrant testing.

Quality Control System: End-to-End Reliability

A high-quality cutting pick depends on an end-to-end quality control system.

Raw material inspection — Chemical analysis of steel to ensure 35CrMo or 42CrMo meets specifications; performance testing of carbide tips for hardness, density, and transverse rupture strength.

In-process control — Dimensional inspection after cold forging; real-time monitoring of furnace temperature, vacuum level, holding time, and cooling rate during heat treatment; visual and penetrant inspection of brazed welds.

Finished product inspection — Hardness testing (40–45 HRC for body, ~60 HRC for wear layer); metallographic analysis of microstructure; impact testing of samples; dimensional and visual inspection for cracks, burrs, and other defects.

Customization — Based on special customer requirements, adjustments can include shank diameter and length for specific equipment; different carbide grades for specific rock conditions; wear layer thickness and distribution; and tip shape (conical, spherical, wedge-shaped, etc.).

Trends and Outlook

Cutting pick technology is moving toward higher efficiency, longer life, and intelligence.

New carbide materials — Gradient carbide (cobalt content varying from surface to core: high-wear surface, high-toughness core); ultra-fine grain carbide (WC grain size under 0.5 μm, increasing both hardness and strength); cobalt-free or low-cobalt carbide (using nickel or iron-based binders to reduce dependence on strategic cobalt).

Surface coatings — PVD or CVD hard coatings (TiN, TiAlN, AlCrN) on tips and wear layers further reduce friction and adhesion, extending life.

Biomimetic and optimized design — Pick shapes inspired by pangolin claws or beetle shells; finite element analysis (FEA) widely used to reduce stress concentrations.

Smart monitoring — Sensors on large mining equipment monitor cutting motor current fluctuations and vibration signals to indirectly assess pick wear — enabling "change on condition" instead of fixed schedules.

Remanufacturing and recycling — Worn picks can be rebuilt by hardfacing or tip replacement. A remanufactured pick costs 40–60% of a new one and lasts over 80% as long.

Industry research shows the global Cutting pick market was about $1.8 billion in 2023, projected to reach $2.5 billion by 2030 — about 4.2% annual growth. China — the world's largest coal producer and a major tunneling market — accounts for 35–40% of global consumption.

The Bottom Line

The cutting pick — a core wear-resistant component in mining — is small but carries a huge responsibility. From careful selection of 35CrMo and 42CrMo high-quality steel, to precision cold forging; from vacuum heat treatment for precise hardness control, to the strong brazed connection between YG11C carbide tip and steel body; from the cleverly designed 60 HRC wear layer, to the end-to-end quality control system — every pick embodies materials science, metallurgy, and mechanical engineering. Facing applications from soft coal to hard rock, from mines to tunnels, the cutting pick — with its series-based, customizable technology system — continues to provide efficient, reliable cutting solutions for global excavation projects. As new materials, new processes, and smart technologies continue to advance, this seemingly traditional consumable tool is gaining new life.