Quality Nickel Alloy Casting & Cobalt Alloy Castings factory

The fineness of PA11 powder used for wire basket coating is usually selected according to the specific coating process: Micro-coating process: If the micro-coating process is adopted, the powder diameter is generally about 55μm, which is more suitable. Such fineness can control the coating thickness at 100-150μm, and can form a relatively uniform and moderately thick coating on the surface of the wire basket, providing good protection and appearance. Electrostatic spraying: For electrostatic spraying process, a powder diameter of 30-50μm is a better choice. Powders of this fineness can be better adsorbed on the surface of the wire basket under the action of static electricity, and can make the coating thickness reach 80-200μm, which not only ensures the adhesion of the coating, but also can adjust the coating thickness as needed to meet different usage requirements. In addition, the choice of powder fineness may also be affected by factors such as the use environment of the wire basket and the specific requirements for coating performance. For example, if the wire basket needs to be used in a highly corrosive environment, a thicker coating may be required. At this time, if the process permits, a slightly coarser or finer powder can be selected to adjust the coating thickness and density; if the surface smoothness of the coating is very high, a finer powder may be required to obtain a finer surface.

Which parts of glasses are suitable for it? Grades of pure titanium and their applications in eyeglass frames I. Main grades and characteristics of pure titaniumPure titanium refers to materials with a titanium content of ≥99%. According to the purity and performance differences, the common grades are as follows:1. ASTM Grade 1 (TA1)Purity: The titanium content is about 99.5%, and the impurity content (iron, oxygen, etc.) is extremely low.Performance:The density is only 4.5g/cm³, which is the lightest grade of pure titanium. It has excellent ductility (can be cold processed into extremely thin plates), but the strength is relatively low.It has excellent corrosion resistance, especially strong resistance to daily corrosive media such as sweat and cosmetics.Application parts:Tempers: Using its flexibility, it can fit the ears naturally when worn to reduce the sense of pressure.Nose bridge parts: such as nose bridge brackets or nose bridge connectors of frameless glasses, which are not easy to break when they need to be adjusted frequently.Ultra-thin frames: pursue the ultimate lightweight design (such as frame frames with a thickness of less than 1mm).2. ASTM Grade 2 (TA2)Purity: Titanium content is about 99.2%, and the impurity content is slightly higher than Grade 1.Performance:Strength is about 10%-15% higher than Grade 1 (tensile strength ≥345MPa), while maintaining good processability and corrosion resistance (better than stainless steel).Better high temperature resistance (can withstand temperatures below 300℃), suitable for surface treatment (such as anodizing coloring).Application:Frame body: such as the front frame of full-frame glasses and the metal frame beam of half-frame glasses, which need to take into account both strength and lightness.Template body: More suitable for making medium and long temples than Grade 1 to avoid deformation due to excessive softness.High-end pure titanium frame: Japanese brands (such as Kaneko and Masunaga) often use TA2 for pure titanium glasses, which have a delicate texture and outstanding durability. II. The core advantages of pure titanium in glassesLightweight and comfort: The density of pure titanium is only 1/2 of that of steel. It does not feel oppressive when worn for a long time. It is suitable for users with high myopia or weight sensitivity.Biological compatibility: Almost no metal ion release, less irritation to the skin, suitable for people with allergies.Corrosion resistance: It is not easy to rust or discolor after long-term contact with sweat and skin care products, which extends the service life of the frame.Design flexibility: It can be made into ultra-thin, hollow and other complex shapes through cold processing, suitable for minimalist or artistic design (such as Lindberg's pure titanium screwless frame). III. The logic of choosing different grades of pure titaniumPursue extreme lightness: Choose Grade 1 (TA1), suitable for non-load-bearing parts such as temples and nose bridges.Taking into account both strength and texture: Choose Grade 2 (TA2), suitable for parts that need to support lenses such as the frame body and full frame structure.Surface treatment requirements: Grade 2 has higher strength and better color stability after anodizing than Grade 1, suitable for color frame design.Example scenario: In a pair of pure titanium frameless glasses, the nose bridge connection may use Grade 1 (flexible and easy to adjust), while the metal studs that fix the lenses are Grade 2 (strong enough to support the weight of the lenses).

The design drawings of customized aluminum alloy forgings must be closely integrated with the forging process characteristics to avoid forming difficulties, mold loss or performance defects caused by unreasonable structural design. The following is an analysis of the structural elements, dimensional tolerances, process identification and other dimensions combined with the aluminum alloy forging characteristics: I. Process adaptability of structural design 1. Avoid extreme structural features Taboo structure Risk manifestation Improvement plan Deep hole (hole depth / hole diameter > 5:1) Punch is easy to bend and break, and the hole wall is not fully filled Use stepped hole segmented forming to reserve subsequent drilling allowance High rib (rib height / wall thickness > 3:1) Metal flow is blocked, and the rib part is lacking in filling Stepped rib design to increase the transition slope Thin wall (wall thickness < 2mm) Fast cooling during forging, easy to fold Partial thickening to 3-4mm, subsequent machining thinning Case: The design drawing of an aluminum alloy motor housing has a Φ10mm deep hole (hole depth 55mm). The punch was severely worn during forging, so it was later changed to a Φ10mm×30mm blind hole +Φ8mm×25mm stepped hole. The forming qualification rate was increased from 40% to 92%. 2. Differentiated design of draft angleCorresponding angles of alloy series:6 series (6061/6082): outer wall 5°-7°, inner wall 7°-10° (good plasticity, slightly smaller angle);7 series (7075/7A04): outer wall 7°-10°, inner wall 10°-15° (strong quenching tendency, angle needs to be increased to prevent jamming);2 series (2024/2A12): outer wall 6°-8°, inner wall 8°-12° (avoid demoulding cracks caused by too small angle).Structural optimization: For deep cavity structures (such as battery housings), variable angle design is adopted: 10° for the upper section, 8° for the middle section, and 5° for the lower section, with ejection mechanism to assist demoulding. 3. Mechanical matching of fillet radiusCalculation of minimum fillet radius (Rmin):Rmin = 0.2× wall thickness + 2mm (applicable to 6 series);Rmin = 0.3× wall thickness + 3mm (applicable to 7 series / 2 series).Example: For 7075 forgings with a wall thickness of 5mm, the corner R should be ≥0.3×5+3=4.5mm to avoid stress concentration cracking when R＜3mm.Treatment of special parts: Elliptical transition is used at the connection between ribs and webs (the long axis is along the metal flow direction), such as the design of R8×R12 elliptical fillet at the connection of the ribs of a certain bracket to reduce the risk of forging folding. II. Dimensional tolerance and machining allowance design1. Forging process adaptation of tolerance band Linear dimension tolerance (refer to GB/T 15826.7-2012): Size Range (mm) 6 Series Normal Accuracy (mm) 7 Aeries Precision Grade (mm) ≤50 ±0.5 ±0.3 50-120 ±0.8 ±0.5 120-260 ±1.2 ±0.8 Geometric tolerance control: flatness ≤ 0.5mm/100mm, verticality ≤ 0.8mm/100mm, thin-walled parts (wall thickness < 5mm) need to be tightened to 1/2 standard value. 2. Three-dimensional distribution of machining allowanceRadial allowance: 3-5mm (free forging), 1.5-3mm (die forging) for outer cylindrical surface; 4-6mm (free forging), 2-4mm (die forging) for inner hole surface.Axial allowance: 2-4mm is left on each end surface. For shaft parts with aspect ratio > 3, 1-2mm anti-warping allowance needs to be added in the middle section.Allowance compensation: For 7 series forgings, due to the large quenching deformation, the key size allowance needs to be increased by 20%-30%, such as the inner diameter allowance of a 7075 flange increased from 3mm to 4mm. III. Process identification and special requirements1. Mandatory marking of fiber flow directionMarking method: Use arrows to indicate the fiber direction in the cross-sectional view. The angle between the fiber direction and the principal stress direction is required to be ≤15° in the key stress-bearing parts (such as the hub bolt hole area).Prohibited design: Avoid the stress direction of the forging being perpendicular to the fiber direction (such as when the gear tooth direction is perpendicular to the fiber, the bending strength decreases by 30%).2. Design of parting surface and process bossParting surface selection principle:Located at the maximum cross-section of the forging to avoid misalignment caused by asymmetric parting;The roughness of the parting surface of the 7 series forgings is Ra≤1.6μm to prevent burrs caused by tearing of the flash.Process boss design: For asymmetric forgings (such as L-shaped brackets), a Φ10-15mm process boss needs to be designed for positioning. The boss is subsequently machined and removed, and the position is selected in the non-stress area.3. Heat treatment status and flaw detection requirementsStatus identification: The drawing title bar must indicate the status of T6/T74/T651, etc. For example, when the 2024 forging requires the T4 status, it must be marked as "solution treatment + natural aging". Non-destructive testing terms:Important parts (such as chassis parts): 100% ultrasonic flaw detection (acceptance level ≥ GB/T 6462-2017 II level);Aerospace-grade forgings: Add fluorescent penetration testing (sensitivity level ≥ ASME V 2 level). IV. Typical failure cases and improvement plans1. Case: 6061 automobile control arm crackingOriginal design problem: The wall thickness of the web in the middle of the arm body changes suddenly (from 8mm→3mm), the transition radius is R2mm, and cracks at the sudden change after forging.Improved design: The wall thickness changes gradually (8mm→5mm→3mm), and the transition zone is set with an angle of R8mm+45°, and the cracking problem disappears.2. Case: 7075 aviation joint size out of toleranceOriginal tolerance setting: diameter Φ50mm±0.3mm (die forging), the out of tolerance rate due to quenching shrinkage in actual production reached 50%.Improvement plan: mark "4mm machining allowance after hot forging, fine turning to Φ50±0.05mm after quenching", and the qualified rate is increased to 98%. V. Design tools and standard references1. CAE simulation-assisted designUse Deform-3D to simulate metal flow and optimize draft angle and fillet: For example, the simulation of a complex shell shows that the metal flow rate difference at the R5mm fillet of the original design is 20%, and the flow rate difference is reduced to 5% after changing to R8mm.2. Industry standard referencesDomestic: GB/T 15826-2012 "Machining allowance and tolerance of steel die forgings on hammer";International: ISO 8492:2011 "Aluminum and aluminum alloy forging tolerances". In summary, the design of aluminum alloy forging drawings needs to deeply couple material properties (such as quenching sensitivity of the 7 series), forging processes (such as metal flow laws of die forging) and structural functions, and ensure the manufacturability and performance of forgings through reasonable draft angles, fillet radii, allowance allocation and process identification. It is recommended to collaborate with forging manufacturers in the design stage and avoid process risks in advance through DFM (design for manufacturability) analysis. Email: cast@ebcastings.com

Will excessive temperature cause cracking? Heating temperature control of aluminum alloy forgings is the core link to ensure the quality of forgings. Excessive temperature may not only cause cracking, but also cause various defects. The following is an analysis of temperature control technology, temperature influence mechanism and preventive measures: I. Precise control technology of heating temperature 1. Temperature threshold setting based on alloy grade Alloy Series Commonly used Grades Start Forging Temperature Range (℃) End Forging Temperature Lower Limit (℃) Danger Temperature Range (℃) 6 series 6061/6082 480-520 ≥350 >550 (overheating critical temperature) 7 series 7075/7A04 400-450 ≥320 >470 (grain boundary melting temperature) 2 series 2A12/2024 460-490 ≥380 >500 (eutectic phase melting temperature)   Example: When a company forges 7075 battery shells, it uses segmented temperature control: in the preheating stage, it is kept at 400℃ for 2h, and then heated to 430℃±5℃ constant temperature to ensure that the β phase (MgZn₂) is fully dissolved, while avoiding the melting of the low melting point eutectic (475℃) at the α+β phase boundary. 2. Heating equipment and temperature control system Gas furnace segmented temperature control: a three-chamber continuous heating furnace (preheating chamber 400℃, heating chamber 450℃, and equalizing chamber 430℃) is used, with an infrared thermometer (accuracy ±3℃), and the furnace temperature uniformity is controlled within ±10℃. Precise control of electric heating furnace: the vacuum resistance furnace uses the PID intelligent temperature control system to heat up to the set temperature at a rate of 5℃/min, and the fluctuation in the insulation stage is ≤±5℃, which is suitable for sensitive alloys such as the 7 series. Dynamic compensation of induction heating: For complex-shaped forgings (such as multi-cavity structures of battery shells), medium-frequency induction heating (frequency 20-50kHz) is used to locally compensate the temperature through the eddy current effect, so that the cross-sectional temperature difference is less than 15°C. 3. Temperature field simulation and real-time monitoring CAE simulation before forging: Deform-3D is used to simulate the heating process and predict the temperature distribution of the billet. For example, the simulation of a certain L-shaped battery bracket forging shows that the temperature at the corner is 20°C lower than that on the plane. In actual production, it is compensated by partition heating coils. Online infrared thermal imager: Scanning speed 100 frames/second, real-time generation of temperature cloud map, when local over-temperature is detected (such as > set value 15°C), the system automatically starts the air cooling device to cool down.   II. Analysis of the mechanism of cracking caused by excessive temperature 1. Structural defects caused by thermal damage Three characteristics of overburning: Oxidation triangles appear at grain boundaries (when the temperature is greater than the eutectic melting point, Mg₂Si and other phases melt); Grain boundaries widen and form a network (for example, when 6061 aluminum alloy is heated at 560℃ for 20min, the liquid phase ratio at the grain boundaries reaches 3%); Remelting balls appear between dendrites (7075 aluminum alloy is kept at 480℃ for 1h, and the Al-Zn-Mg phase between dendrites melts). Granular and weak grains: When the temperature exceeds the upper limit of the recrystallization temperature (such as 460℃ for 7075), the grain size grows rapidly from 10-20μm in the forged state to more than 500μm, the plasticity decreases by 40%, and cracks occur along the grain boundaries during forging. 2. Stress concentration induces cracking Temperature difference stress cracking: When the heating rate is too fast (e.g. >15℃/min), the temperature difference between the surface and the core of the forging is >50℃, generating thermal stress (σ=EαΔT). When σ> material yield strength (e.g. 7075 at 400℃ σs=120MPa), cracking occurs. Phase transformation stress superposition: When the 2-series aluminum alloy is heated to 500℃, the dissolution rate of the θ phase (CuAl₂) is uneven, and the local phase transformation stress is superimposed on the forging stress, causing the crack to extend along the grain boundary.   III. Anti-cracking process countermeasures 1. Gradient heating and insulation control Step-type heating curve: Low temperature section (200-300℃): heating rate 5℃/min, eliminate the internal stress of the billet; Medium temperature section (300-400℃): rate 10℃/min, promote uniform distribution of the second phase; High temperature section (400 - set temperature): rate 5℃/min, ensure uniform temperature. Insulation time calculation: according to billet thickness (mm) × 1.5-2min/mm, for example, 100mm thick 7075 billet, 430℃ insulation for 2.5-3h, so that the strengthening phase is fully dissolved. 2. Die preheating and isothermal forging Mold temperature matching: before forging, the mold is preheated to 250-300℃ (6 series) or 180-220℃ (7 series) to reduce the temperature difference stress caused by rapid cooling of the forging. Isothermal forging technology: Forging at a low speed of 0.01-0.1mm/s on a servo press, while the built-in heating rod in the mold maintains the billet temperature at ±3℃, which is suitable for complex thin-walled battery shells (wall thickness 0.2mm, the microcracks under the oxide scale will expand at high temperature), and use shot peening or alkali washing for pretreatment. Non-destructive testing control: 100% ultrasonic flaw detection (frequency 2.5-5MHz) after forging to detect grain boundary loosening caused by overburning (reflection amplitude ≥φ2mm flat bottom hole equivalent).   Email：cast@ebcastings.com      

In the production of magnesium castings, the realization of environmental protection requirements needs to run through the entire process of smelting, casting, and post-processing, and smelting flue gas treatment is a key link. The following is an explanation from two aspects: environmental protection measures system and flue gas treatment technology:   一. Environmental protection measures for the entire process of magnesium casting production 1. Smelting link: source pollution control and energy optimization Low-pollution smelting technology Use inert gas protection smelting (such as CO₂, SF₆ mixed gas) to replace traditional fluoride salt flux and reduce the emission of toxic gases such as hydrogen fluoride (HF) and chlorine (Cl₂). For example, a German factory uses CO₂+0.1% SF₆ protection, and the fluoride concentration in the flue gas is reduced from 50mg/m³ to below 5mg/m³ (EU emission standard is 10mg/m³). Promote the use of electric induction melting furnaces to replace oil furnaces, increase the power conversion rate to 85% (oil furnaces are about 60%), and reduce NOx emissions by 40%-60%. Waste recovery and energy consumption control Establish a closed circulation system to process magnesium chips, gate materials and other waste materials through crushing-screening-remelting, with a recovery rate of more than 95%. A domestic enterprise reduces solid waste emissions by 2,000 tons and energy consumption by 12% each year through direct waste remelting technology. 2. Casting and post-processing: process innovation to reduce pollution Less/no cutting process High-pressure die casting achieves near-net forming of magnesium castings (dimensional tolerance ±0.1mm), reduces machining processes, reduces cutting fluid usage by 70%, and reduces waste generation by 50%. Green surface treatment Use chromium-free passivation (such as silane treatment, rare earth conversion film) instead of hexavalent chromium electroplating, and wastewater COD (chemical oxygen demand) is reduced from 500mg/L to below 100mg/L. For example, a new energy vehicle battery shell uses silane coating, which has a salt spray test of 1,000 hours without corrosion, and reduces wastewater treatment costs by 30%. 3. Comprehensive waste management Wastewater treatment Establish a three-level treatment system: regulating tank (neutralizing pH value) → chemical precipitation (removing heavy metal ions) → membrane filtration (COD removal rate 90%), the effluent can be reused in the cooling system, and the water reuse rate reaches 85%. Classification and disposal of solid waste After the smelting slag is magnetically separated to recover magnesium metal, the remaining slag is used to produce refractory materials; the waste release agent is regenerated by distillation, and the recovery rate reaches 80%.   二. Core technology for magnesium smelting flue gas treatment 1. Flue gas composition and characteristics Main pollutants: MgO dust (accounting for 60%-70%), fluoride (HF, MgF₂), trace metal vapor (such as Zn, Pb) and organic volatiles (decomposition products of release agent). Flue gas characteristics: high temperature (300-500℃), fine dust particle size (0.1-10μm), and highly corrosive fluoride. 2. Mainstream treatment technologies and process combinations (1) Dry purification technology Bag dust removal + activated carbon adsorption Principle: The flue gas is first cooled to 120-150℃ by the waste heat boiler, then passed through a bag dust collector (filter bag material is PTFE, filtration efficiency ≥99.9%) to remove MgO dust, and finally through an activated carbon adsorption tower to remove fluoride and organic pollutants. Case: A magnesium alloy wheel hub factory adopts this process, and the dust emission concentration is