The durability of tungsten carbide granulator knives depends not only on the tungsten carbide material (cobalt content, grain size) but also closely on the production process. Currently, the mainstream production processes are divided into two categories: "welded type" and "integral type". The welded type involves brazing a tungsten carbide tip onto an alloy steel base, while the integral type is made of full tungsten carbide through powder metallurgy sintering. These two processes differ significantly in structural strength, impact resistance, wear performance, and applicable scenarios. Many practitioners mistakenly believe that "integral full tungsten carbide is more durable", but this is not the case: the welded type, with toughness compensation from the steel base, is more suitable for complex working conditions with impurities and impact; the integral type, on the other hand, has advantages in high-abrasion, impact-free scenarios. This article explains the processes, conducts core comparisons, and covers scenario adaptation to help industry practitioners clarify the pros and cons of the two processes and select more durable granulator knives accurately.
1. First, Understand: Basic Explanation of the Two Production Processes
- Production Process: First, a tungsten carbide tip (core cutting part) is made through powder metallurgy sintering. Then, silver brazing technology is used to weld the tip onto a 45# steel or alloy steel base. Finally, cutting edge grinding and surface treatment are performed;
- Structural Characteristics: Combination of "tungsten carbide tip + steel base". The tip is responsible for cutting and wear resistance, while the steel base provides toughness and installation fixation. The weld joint is the core connection point;
- Core Advantages: Strong toughness (steel base buffers impact), relatively low cost, and local tip replacement (convenient maintenance);
- Key Notes: Weld quality directly affects durability. Excessively high welding temperature or non-standard welding processes may cause tip detachment or weld cracking.
- Production Process: Tungsten carbide powder (WC) and cobalt powder (Co) are mixed in proportion, pressed into a mold, sintered and formed under high temperature and pressure, and then the cutting edge is processed through precision grinding. There are no additional base or welding steps;
- Structural Characteristics: The entire knife body is made of tungsten carbide, with no weld joints or material splicing, and a uniform overall structure;
- Core Advantages: Ultimate wear resistance (full tungsten carbide with no weak links), strong structural stability, and high cutting precision;
- Key Notes: Toughness depends on the tungsten carbide itself (high-cobalt grades can improve toughness), impact resistance is relatively weak, and the cost is 30%-50% higher than that of the welded type.
2. Core Comparison: Welded vs Integral – PK of Key Durability Dimensions
The following compares the core dimensions affecting the durability of granulator knives, combining process characteristics and actual working conditions to clarify differences at a glance:
| Comparison Dimension | Welded Tungsten Carbide Granulator Knives | Integral Tungsten Carbide Granulator Knives |
|---|---|---|
| Structural Composition | Tungsten carbide tip (3-8mm thick) + alloy steel base | Full tungsten carbide integrated molding (overall thickness 8-15mm) |
| Core Stress-Bearing Parts | Weld joint + tungsten carbide tip edge | Entire knife body (no weak connection points) |
| Wear Resistance | Tip is wear-resistant (equivalent to integral type), base does not participate in cutting | Full knife body is wear-resistant (no wear difference), larger wear-resistant area |
| Impact Resistance | Strong (steel base buffers impact, not easy to chip when weld is qualified) | Medium (depends on tungsten carbide cobalt content, low-cobalt grades are prone to chipping) |
| Durability Shortcomings | Weld is prone to corrosion or cracking (under harsh conditions), tip may detach | Insufficient impact resistance (prone to chipping in impurity-containing materials), high cost |
| Adaptable Materials | Impurity-containing materials (e.g., recycled plastic, biomass, waste rubber), high-impact working conditions | Impurity-free materials (e.g., new plastic, high-purity pellets), high-abrasion impact-free working conditions |
| Adaptable Granulator Types | Flat-die granulators, low-speed granulators (high impact) | Ring-die granulators, high-speed granulators (low impact) |
| Service Life (Relative Value) | 1.0 (benchmark, conventional working conditions) | 1.2-1.5 (high-abrasion impact-free conditions) / 0.6-0.8 (impact conditions) |
| Cost per Knife (Relative Value) | 1.0 (benchmark) | 1.3-1.5 |
| Maintenance Cost | Low (tip can be replaced individually, no need for overall scrapping) | High (overall scrapping when knife body chips, no repair value) |
| Common Failure Modes | Tip detachment, weld cracking, tip wear | Edge chipping, overall blunting, knife body fracture |
Supplementary Notes:
- Essential difference in wear resistance: When the tungsten carbide tip/body materials of the two processes are consistent, their wear resistance is almost the same. The "lack of durability" of the welded type mostly stems from weld problems, not the tungsten carbide itself;
- The "durability advantage" of the integral type is only reflected in impact-free, high-abrasion scenarios. If used in impurity-containing, high-impact working conditions, its insufficient impact resistance will lead to frequent chipping, making it less durable;
- Weld quality is critical for the welded type: Products using silver brazing + vacuum welding processes can achieve weld strength of more than 80% of the base strength, significantly improving durability. Low-cost products mostly use ordinary brazing, which is prone to detachment.
3. Key Factors Affecting Durability: More Than Just the Process, These Details Matter
3.1 Welded Granulator Knives: Weld Quality Determines the "Service Life Ceiling"
- Welding Process: Vacuum welding ＞ Argon arc welding ＞ Ordinary brazing. Vacuum welding avoids weld oxidation and reduces cracking risks;
- Tip Fixation Method: In addition to welding, some high-end products adopt "welding + mechanical clamping" dual fixation to further improve connection strength;
- Base Treatment: Anti-corrosion treatment (e.g., nitriding, painting) on the steel base surface can avoid weld failure caused by corrosion in working conditions.
3.2 Integral Granulator Knives: Material Uniformity Determines "Wear Stability"
- Sintering Process: Hot pressing sintering ＞ Cold pressing sintering. Hot-pressed sintered tungsten carbide has higher density and more uniform material, avoiding chipping caused by internal pores;
- Material Formula: Integral granulator knives with high cobalt content (e.g., YG10/YG12) have better toughness, impact resistance close to that of welded types, and a wider range of applicable scenarios;
- Edge Treatment: Micro-chamfering and polishing of the edge can reduce stress concentration and lower the probability of chipping.
4. Selection Guide: Which Process is More Durable? Precise Selection by Working Condition
4.1 3 Scenarios to Prioritize the Welded Type
- Impurity-containing materials (e.g., sediment in recycled plastic, sand grains in biomass, fibers in rubber): The toughness of the steel base can buffer impurity impact and avoid tip chipping;
- Granulators with high impact (e.g., flat-die granulators, low-speed heavy-load equipment): The impact resistance of the welded type is more suitable, and overall failure is less likely;
- Limited budget or pursuit of low maintenance costs: The welded type has lower cost, and the tip can be replaced individually without overall scrapping.
4.2 3 Scenarios to Prioritize the Integral Type
- Impurity-free materials (e.g., new PE/PP/PET, high-purity biomass): Under impact-free working conditions, the full tungsten carbide structure of the integral type is more durable;
- High-abrasion materials (e.g., PET bottle flakes, siliceous biomass): The integral type has a larger wear-resistant area, avoiding the problem of base exposure after tip wear in the welded type;
- High-precision granulation requirements (e.g., medical plastic, precision pellets): The integral type has stable structure, high cutting precision, and better pellet uniformity.
4.3 3-Step Selection Method (Quick Matching)
- Check Material Impurities: Impurity-containing → Welded type; Impurity-free → Integral type;
- Check Impact Intensity: Flat-die granulators, low-speed heavy-load → Welded type; Ring-die granulators, high-speed light-load → Integral type;
- Check Budget: Limited budget, pursuit of low maintenance → Welded type; Sufficient budget, pursuit of ultimate wear resistance → Integral type.
5. Common Misconceptions: These Perceptions Affect "Durability Judgment"
Misconception 1: Integral full tungsten carbide is always more durable
Truth: It is only more durable under impact-free and impurity-free working conditions. In impurity-containing, high-impact conditions, the integral type is prone to chipping and even less durable than the welded type.
Misconception 2: Welded tips are easy to detach
Truth: For high-quality welding (vacuum silver brazing) + reasonably structured products, the probability of tip detachment is extremely low. Detachment mostly occurs in low-cost ordinary brazing products.
Misconception 3: The integral type has high cost and low cost-effectiveness
Truth: Under high-abrasion, impact-free working conditions, the service life of the integral type is 1.2-1.5 times that of the welded type, and the comprehensive cost (service life ÷ unit price) is actually lower.
6. Typical Application Cases (Intuitive Reference)
| Application Scenario | Material Type | Granulator Type | Recommended Process | Durability Performance |
|---|---|---|---|---|
| Waste PP Plastic Recycling Granulation | PP fragments (3-5% sediment impurities) | Flat-die granulator (low-speed) | Welded type (vacuum welding) | No tip detachment, service life 800-1000 hours |
| New PET Granulation | Pure PET bottle flakes (impurity-free) | Ring-die granulator (high-speed) | Integral type (YG8) | No chipping, service life 1200-1500 hours |
| Biomass Straw Granulation | Straw (siliceous, with impact) | Flat-die granulator | Welded type (dual fixation) | Stable weld, service life 600-800 hours |
| High-Purity PE Film Granulation | New PE film (impurity-free) | High-speed granulator | Integral type (YG6X) | Durable wear resistance, service life 1000-1200 hours |
Conclusion: There is No "Absolutely More Durable" Process, Only the "More Suitable" Choice
The durability of welded and integral tungsten carbide granulator knives essentially lies in the "matching degree between process characteristics and working conditions": the welded type relies on the combination of "tungsten carbide wear resistance + steel base impact resistance" to adapt to complex impurity conditions; the integral type leverages the advantage of "full tungsten carbide with no weak links" to adapt to high-abrasion pure conditions.
As a tungsten carbide industry practitioner, it is recommended to first understand the customer's material impurity content, granulator type, and impact conditions before recommending products: select the welded type for impurity-containing, high-impact scenarios (focusing on weld process), and the integral type for impurity-free, high-abrasion scenarios (focusing on tungsten carbide cobalt content). For special working conditions (e.g., high impact + high abrasion), a customized welded type solution with "high-cobalt tungsten carbide tip + reinforced weld + thickened base" can be adopted to balance wear resistance and impact resistance.
If you need to recommend more precise process and material configurations based on specific materials and granulator parameters, please contact us for customized advice to help improve granulator knife durability and reduce comprehensive costs!