I. Raw‑material Level, the Fundamental Gap in Quality
1. Differences in base steel for pick bodies High‑quality rotary drilling picks adopt 42CrMo chromium‑molybdenum alloy structural steel for pick bodies. Premium hard‑rock‑type picks use 40CrNiMo nickel‑chromium‑molybdenum alloy steel. Steel raw materials are original bars from formal steel mills, with contents of harmful impurities such as sulfur and phosphorus strictly compliant with standards. Each blank must undergo forging treatment to form continuous and dense metal fibre structures without internal air holes, shrinkage cavities or slag inclusions. The picks deliver excellent shock‑resistance, bending‑resistance and fatigue‑resistance capacity, capable of enduring repeated impact and vibration from cobblestone and hard‑rock strata for a long time. Most low‑cost inferior picks are manufactured from ordinary 45‑carbon steel, recycled remelted scrap steel and crude continuous‑cast billets with severely deficient alloy elements. Their blanks are mostly sand‑cast or directly lathed from raw materials without forging procedures. The loose‑textured steel contains inherent tiny sand holes and stress defects, which easily lead to shank fracture and bending cracks on the pick body during construction.
2. Differences in tungsten‑carbide cutter tip materials High‑quality picks select original tungsten‑cobalt carbide of corresponding grades according to construction strata. Coarse‑grained YG8C and YG11C carbide are applied for cobblestone‑impact‑prone strata to prioritise impact toughness; fine‑grained YG6X and YG8 carbide are adopted for weathered rock and granite strata to focus on wear resistance. The cobalt proportion inside carbide is authentic and uniform with adequate overall density and neatly‑arranged crystal grains. The surface presents bright metallic luster free of pits, oxidation spots and hidden edge cracks. Inferior picks are all processed from recycled tungsten powder. One single type of carbide is used for all strata with falsely‑marked and chaotic cobalt content. Plenty of internal pores and disordered coarse grains exist inside the carbide. Its outer surface is beautified by polishing while numerous impurities remain inside. Unstable hardness causes frequent chipping and fragmentation against hard stones together with rapid wear‑off speed.
3. Differences in brazing filler metal High‑grade products adopt standard copper‑based brazing materials including manganese‑copper and silver‑copper welding sheets. With proper melting points and high welding bonding strength, the solder firmly bonds carbide tips and pick‑body substrates. Low‑cost picks employ cheap ordinary brass scraps and inferior tin‑lead solder. The solder features poor toughness and weak high‑temperature resistance. Weld seams tend to crack under impact and vibration, directly triggering the falling‑off of tungsten‑carbide tips.
II. Detailed Differences in Production and Processing Technology
1. Gaps in complete heat‑treatment procedures High‑quality picks follow full standardized heat‑treatment workflows. Normalising is conducted after forging to eliminate forging stress. Subsequent integrated quenching and high‑temperature tempering stabilise pick‑body hardness within HRC38‑45 for sufficient substrate toughness. Independent induction quenching is performed on the tip section to reach HRC55‑60 surface hardness, achieving surface wear‑resistance and inner‑layer shock‑resistance. Final low‑temperature stress‑relief tempering removes all residual quenching stress and prevents unprovoked cracks in later‑stage usage. Low‑cost inferior picks skip multiple tempering procedures. Some over‑brittle picks crack once hitting cobblestones; others receive no heat‑treatment at all and wear flat or bend in a short construction period. Poorly‑controlled quenching temperature creates oversized steel grains and greatly shortened service life.
2. Gaps in brazing technology High‑quality picks adopt fully‑automatic high‑frequency induction brazing and vacuum brazing techniques. The assembly clearance between carbide tips and pick bodies is strictly kept from 0.05 mm to 0.15 mm. Welding sheets are placed with fixed dosage. Machines fully control welding temperature, heat‑holding duration and cooling speed. Slow cooling after welding reduces internal weld‑seam stress, and the weld shear strength exceeds 180MPa. Inferior picks are welded manually with flame spray guns. Assembly clearance is random, solder is added based on workers’ experience and temperature is judged purely by personal feeling. Picks are immediately cooled by cold water after welding, leaving huge internal stress inside weld seams. Hidden defects such as false welding, air holes, slag inclusions and weld gaps commonly exist.
3. Differences in wear‑resistant surfacing technology Hard‑rock‑specialised high‑quality picks adopt plasma surfacing and laser cladding technology. A 2‑4‑mm‑thick tungsten‑carbide wear‑resistant coating is clad on the outer layer of pick tips. Metallurgical bonding connects the coating and substrate to avoid large‑scale peeling with uniform and stable surface hardness. Cheap products only complete a thin layer of wear‑resistant material via manual electric‑arc surfacing, with the coating thickness below 1 mm. Poor bonding strength causes the wear‑resistant layer to peel off soon after construction. Some small workshops even use paint to disguise the wear‑resistant coating.
4. Gaps in machining precision High‑quality picks are finely processed by CNC lathes with all dimensional tolerances controlled within ±0.05 mm. The pick shank owns standard cylindricity, and snap‑ring grooves, sealing grooves and mounting threads achieve precise dimensions. When fitted into pick holders, picks maintain proper tightness and rotate freely and smoothly to reduce unilateral eccentric wear. Low‑cost picks are processed by outdated ordinary lathes with dimensional errors reaching 0.3‑0.5 mm. The pick shank suffers oval and tapered deformation. After installation, picks either get stuck and cannot rotate or shake violently due to excessive clearance. Offset grooves and burr‑covered threads disable normal assembly of matched snap rings and sealing rings.
III. Visible Identification Details through Appearance and Markings
1. Appearance of hard‑alloy cutter tips High‑quality tungsten‑carbide tips feature smooth and delicate surfaces without pits, sand holes or tiny hidden cracks. The top arc transitions smoothly and regularly. Carbide tips stay coaxial with pick bodies without offset or inclination. Inferior carbide tips present dull‑grey surfaces covered with tiny pits and frequently chipped edges. Offset carbide tips usually cause severe unilateral wear during operation.
2. Features of welding seams Qualified picks feature full‑circle welding seams with uniform width and sufficient filling, presenting golden copper‑weld colour. No holes, black spots or broken gaps appear on weld surfaces. Defective picks own uneven, rough and pitted welding seams containing air holes and slag residues. Many workshops cover welding defects with glue, putty and black paint.
3. Surface condition of pick‑body substrates High‑quality picks go through shot‑blasting and sand‑blasting treatment, delivering fine and uniform metallic matte surfaces free of folding cracks, iron oxide scales and collision‑induced burrs. Faint forged metal textures can be observed. Rough cast‑type inferior pick bodies are covered with numerous casting sand holes. Thick‑layer paint is adopted to conceal steel‑material defects, and sharp burrs spread over all edges.
4. Engraved marks and factory‑release documents Formal high‑quality products adopt laser marking or electric‑corrosion engraving for clear and deeply‑etched specifications, sizes, manufacturer logos and production batch numbers. Each batch is equipped with material inspection reports, heat‑treatment parameter documents and factory‑release certificates to achieve full‑product traceability. Low‑cost inferior picks carry vague and shallow stamps. Many have zero specification marks with random false labels. No material‑inspection files are provided, and messy batches cannot be traced.
IV. Basic Inspection and Distinction through Size and Weight
1. Parameter measurement with vernier callipers Measure the overall pick length, shank diameter, carbide‑tip diameter, exposed carbide height and groove specifications with vernier callipers. Qualified products show minor deviations from standard drawings. Inferior picks suffer severe dimensional deviations and shortened exposed carbide height to cut tungsten‑carbide consumption.
2. Weight comparison of picks Picks with identical specifications adopt solid raw‑materials and maintain stable weight ranges. Low‑cost counterfeit products deliberately thin shank walls and shrink carbide‑tip dimensions. Their total weight is 5%‑15% lighter than standard‑grade picks, and the weight gap can be distinguished by hand‑held feeling.
3. Assembly test Install picks into matched pick holders. High‑quality picks rotate smoothly with moderate tightness and free spinning capacity. Inferior picks shake violently or get stuck after assembly. Failed free rotation brings about rapid unilateral wear.
V. Simple Non‑destructive On‑site Inspection Methods without Professional Equipment
First, knocking‑test. Gently tap the tungsten‑carbide tip with a small hammer. A crisp and heavy sound stands for firm welding; a dull and hollow sound indicates incomplete welding and internal gaps. Second, grinding‑test. Lightly grind the carbide tip with an angle grinder. High‑hardness qualified carbide creates large grinding resistance and sparse sparks. Soft recycled inferior carbide generates dense flying sparks and rapid surface scratches. Third, hardness‑test. File the rear pick shank with a fine‑tooth file. Properly heat‑treated high‑quality steel resists filing action. Inferior steel with insufficient hardness produces iron filings effortlessly. Fourth, magnet‑adsorption‑test. High‑purity hard alloy barely carries magnetism and will not be attracted by magnets. Impure recycled carbide is mostly magnetic and can be stuck by magnets. Fifth, high‑temperature‑test. Briefly bake the carbide tip over an open flame. Premium carbide resists oxidation and blackening under high‑temperature conditions. Inferior carbide quickly turns black and develops tiny surface cracks after heating.
