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Behind a single millimeter-sized ball lies an entire system of micron-level precision. Introduction In valve seals, VCM motors, precision bearings, and inspection fixtures, tiny precision balls — bearing steel balls, ceramic balls, cemented carbide (tungsten carbide) balls — are critical components that are easy to overlook. When selecting balls, engineers and buyers often get lost in grade designations such as G3, G5, and G10. If a drawing says “G5,” is that the same ball under the Chinese national standard, the U.S. ABMA, ISO, German DIN, and Japanese JIS? And what do all those symbols — Vdws, ΔSph, Vdwl — actually mean on the shop floor? This article skips the theory and answers three things: how the five major standards relate to each other, how to read the five core metrics, and where buyers most often go wrong. 01 Five major standards: one ball, five sets of rules Five precision systems are most commonly referenced in the industry: Standard Full name Where it is typically used GB/T 308.1 Chinese National Standard — rolling bearing balls General standard for bearing steel balls in China; cemented carbide balls refer to JB/T 9145 ABMA 10A American Bearing Manufacturers Association North American equipment, imported valves, foreign-invested projects ISO 3290 International Organization for Standardization The global baseline; most national standards are modeled on it DIN 5401 German Institute for Standardization (DIN) European precision equipment and German-made machinery JIS B 1501 Japanese Industrial Standard Japanese equipment, and spares for Japanese/Korean production lines Important note: identical grade designations do not mean unconditional interchangeability. Although G3/G5/G10 carry the same numbers across standards, the test criteria, measurement conditions, and sorting rules behind them differ in detail. For export projects, confirm the original standard your customer cites; for domestic substitution projects, select against GB/T 308 together with the actual operating conditions. Grade comparison: the smaller the number after “G”, the tighter the tolerance ISO 3290 is the international baseline, and China’s GB/T 308.1 is substantially equivalent to it. DIN 5401 aligns with the ISO grades, and the JIS B 1501 grade sequence is essentially the same. ABMA 10A was originally written in imperial units, which is why you often see an “A” suffix (G5A, G10A). In plain terms: the smaller the number after the “G”, the smaller the permitted error, and the better the ball’s roundness and dimensional consistency. GB/T 308.1 ISO 3290 DIN 5401 JIS B 1501 ABMA 10A G3 G3 G3 G3 G3 G5 G5 G5 G5 G5A G10 G10 G10 G10 G10A G16 G16 G16 G16 G16A G20 G20 G20 G20 G20A The grade sequences line up, but the actual tolerance limits are governed by the text of each individual standard. 02 Five core metrics: what each symbol actually means Five key metrics, one for each dimension of ball quality. Ball diameter variation (Vdws) — is the ball the same diameter in every direction? In plain terms: measure one ball’s diameter in different directions; Vdws is the difference between the largest and smallest reading. If this value runs high, the ball is effectively a flattened ellipsoid. At high speed that shows up as runout, vibration, and noise. In sealing applications, an ellipsoidal ball cannot form a complete circular sealing line against the seat, which leads directly to leakage. Deviation from spherical form (ΔSph) — how far from a perfect sphere? In plain terms: how far the ball’s outer surface deviates from a mathematically perfect sphere. In a perfect sphere, every point on the surface is the same distance from the center. The larger ΔSph is, the more likely the surface has local high or low spots. Under load, those spots concentrate stress and are prone to denting; at a sealing face, point contact causes seal failure. Where cemented carbide balls run against valve seats, ΔSph is the metric that matters most. Lot diameter variation (Vdwl) — how uniform is the batch? In plain terms: within one delivered lot, the size difference between the largest and the smallest ball. Perfect roundness on a single ball is not enough — every ball in the lot needs to be as close in size as possible. In multi-ball drives, caged bearings, counterweights, and multi-ball positioning, a lot with scattered sizes means uneven loading, jamming, and wobble. Many customers check only single-ball specifications and ignore lot consistency — and that is usually where assembly problems come from later. Surface roughness (Ra) — how smooth is the surface, microscopically? In plain terms: the degree of micro-level unevenness on the ball surface. The lower the Ra value, the smoother the surface. Under high-speed friction, rough surfaces generate heat and wear faster. In precision sealing, even a tiny high spot or scratch becomes a leak path for the medium. After fine grinding, cemented carbide balls can reach Ra 0.01 μm for demanding sealing applications. Nominal diameter deviation — how far from the drawing’s nominal size? In plain terms: how much the actual ball size is allowed to differ from the nominal dimension on the drawing. If the drawing calls for φ3 mm, how many microns plus or minus are permitted? Many engineers look only at the G5 grade and ignore the nominal diameter tolerance band. The grade is a baseline; a drawing can always tighten tolerances further. Two G5 orders can therefore carry quite different dimensional limits. 03 Selection pitfalls: three practical rules Don’t order by grade alone A purchasing specification should not say only “G5 cemented carbide balls”. Write down: the standard and its version (for example GB/T 308.1-2013), the nominal diameter, the limits for the five metrics above, and the surface quality requirement. The more complete the specification, the smaller the surprise on delivery. Replacing an imported part with a domestic ball? Verify the limits first If the original equipment drawing cites ABMA, check that the limits for deviation from spherical form, surface roughness, and lot diameter variation are consistent before you substitute a GB/T G5 ball. Confirm the metrics are equivalent first — otherwise you can end up with vibration or seal leakage after

In the field of precision manufacturing, industry attention often focuses on large-scale equipment and complex structural components, making it all too easy to overlook small, basic components. Although cemented carbide balls (commonly known as tungsten steel balls) are unassuming miniature components, they directly determine the sealing precision, transmission stability, and overall service life of precision equipment, making them core industrial components essential for the long-term, stable operation of high-end machinery. At JNE New Material, we manufacture YG and YN series cemented carbide balls in diameters from 0.5 mm to 50 mm, with custom grades and sizes available on request. What Are Cemented Carbide Balls? Cemented carbide balls are high-precision spherical components manufactured using advanced powder metallurgy technology, with tungsten carbide as the hard matrix and cobalt or nickel as the binder phase. The industry primarily categorizes them into two main series: the YG series (tungsten-cobalt alloy) and the YN series (non-magnetic tungsten-nickel alloy). Compared to ordinary steel balls and bearing steel balls, the performance of both series of cemented carbide balls has been comprehensively upgraded. They address the pain points of traditional balls—such as susceptibility to wear, deformation, and corrosion, as well as poor precision—and can be specifically tailored to meet the precision manufacturing needs of different strengths, media, and operating conditions. They are currently the core foundational components in industrial precision manufacturing. Core Physical and Chemical Properties The outstanding adaptability of cemented carbide balls to various operating conditions stems from their stable and superior physical and chemical properties. At the same time, the YG and YN series exhibit significant differences in their properties due to variations in the binder phase material; this is the fundamental reason why these two product lines are suited for different operating conditions. Physical and Chemical Properties of Major Grades ① Physical Properties (by Grade): Property YG3X YG6 YG6X YG8 YG8N YG13 YN6 YN9 YN10 Test Condition Main Composition WC 97% Co 3% WC 94% Co 6% WC 94% Co 6% WC 92% Co 8% WC 91% Co 8% TaC 1% WC 87% Co 13% WC 94% Ni 6% WC 91% Ni 9% WC 90% Ni 10% Material specification Density (g/cm³) 15.0–15.3 14.7–15.0 14.7–15.0 14.5–14.9 14.8–14.9 14.0–14.4 14.5–14.9 14.2–14.6 14.0–14.4 Room temperature (23°C) Rockwell Hardness (HRA) 92–93.5 89.5–91 90–91.5 89–89.5 89.5–91.5 86–88 89–91 89–90 87–89 Room temperature (23°C) Flexural Strength (MPa) 1300–1800 1450–1600 1350–1700 1800–2300 1500–2000 2400–2800 1400–1800 1600–2000 1600–2200 Room temperature (23°C) Fracture Toughness (MPa·m1/2) 10–12 13–14 12–14 14–16 13–15 16–18 12–14 13–15 14–16 Room temperature (23°C) Temperature Resistance (°C) 400–500 400–500 400–500 400–500 400–500 400–500 400–500 400–500 400–500 23–1000°C Wear Resistance (Volumetric Wear Rate, mm³/(N·m)) ≤ 0.005 ≤ 0.008 ≤ 0.007 ≤ 0.01 ≤ 0.009 ≤ 0.02 ≤ 0.01 ≤ 0.015 ≤ 0.02 Dry sliding wear, room temperature Magnetic Properties Magnetic Magnetic Magnetic Magnetic Magnetic Magnetic Non-magnetic Non-magnetic Non-magnetic — ② Chemical Properties (by Grade): Property YG3X YG6 YG6X YG8 YG8N YG13 YN6 YN9 YN10 Test Condition Acid Resistance (Mass Loss Rate, %) < 0.1 < 0.1 < 0.1 < 0.1 < 0.1 < 0.1 < 0.1 < 0.1 < 0.1 Room temperature, 24 h, 10% hydrochloric acid Alkali Resistance (Mass Loss Rate, %) < 0.5 < 0.5 < 0.5 < 0.5 < 0.5 < 0.5 < 0.5 < 0.5 < 0.5 Room temperature, 24 h, 5% sodium hydroxide Resistance to Organic Solvents (Mass Loss Rate, %) < 0.05 < 0.05 < 0.05 < 0.05 < 0.05 < 0.05 < 0.05 < 0.05 < 0.05 72 h at room temperature, in ethanol/acetone High-Temp Oxidation Resistance (Mass Change Rate, %) < 0.2 < 0.2 < 0.2 < 0.2 < 0.2 < 0.2 < 0.2 < 0.2 < 0.2 1000°C, 100 h, in air High-Temp Acid & Alkali Corrosion Resistance (Mass Loss Rate, %) < 0.5 < 0.5 < 0.5 < 0.5 < 0.5 < 0.5 < 0.5 < 0.5 < 0.5 800°C/24 h, 20% sulfuric acid, 5% sodium hydroxide Thermal Shock Resistance (°C) 200–300 200–300 200–300 200–300 200–300 200–300 200–300 200–300 200–300 Rapid heating/cooling, no cracking Note: Data in this table is compiled from published material property tables of major cemented carbide grades and is provided for reference and comparison purposes. Exact values may vary by batch and manufacturing process — contact us for datasheets of specific grades. Full parameter table (including corrosion resistance, thermal conductivity, wear resistance and creep data for each grade): Precision Manufacturing Process The high precision and stability of cemented carbide balls rely not only on high-quality base materials but also on a standardized, meticulous powder metallurgy manufacturing process. Each step is subject to strict control to ensure consistent product quality. Precise Powder Blending: Formulations are tailored to each product series. The YG series uses a tungsten carbide + cobalt-based binder formulation, while the YN series employs a tungsten carbide + nickel-based binder formulation without added cobalt. For certain grades, trace amounts of TiN are added to refine grain size and enhance corrosion resistance. Thorough mixing via wet ball milling ensures uniform powder particle size and composition, establishing the performance differences between the two product lines at the source. Electronics and Digital Industry (YN Series): The YN series is non-magnetic, high-precision, and ultra-clean, free from magnetic interference. It is widely used in VCM (voice coil motors) and precision optical components, performing critical precision transmission functions such as lens autofocus and optical image stabilization. Precision Testing Instruments (YN Series): The YN series features stable material properties, is non-magnetic and corrosion-resistant, and exhibits minimal measurement error. It can be used as indenters for hardness testers, standard calibration spheres, and precision testing fixtures. General Industrial Applications (YG Series): The YG series offers excellent value for money and is wear-resistant and durable. It is widely used in precision bearings, pump seals, mechanical counterweights, sandblasting and grinding, and automated transmission equipment. Selection Guide: YG or YN? For general wear resistance, high-pressure sealing, mechanical counterweights, and general industrial applications, prioritize the YG series, which offers a balance of performance and cost-effectiveness. For non-magnetic environments, precision electronics, optical inspection, chemical corrosion, and high-cleanliness conditions, the YN series must be selected to avoid magnetic interference

主な製品カテゴリー：高精度球状部品、軸受および軸受アセンブリ、バルブ用ボールおよびシート、カスタマイズ可能な精密異形状部品。 加工可能かつ適用可能な材料：セラミックス（ジルコニア、アルミナ、窒化ケイ素、炭化ケイ素等）、超硬合金（YG3X、YG6、YG6X、YG8、YG8N、YG13、YN6、YN9、YN10等）、モネル合金（MONEL K400、MONEL K450、MONEL K500等）、ステンレス鋼（304、316、316L、410、420、440C等）、インコネル合金（Inconel 600、Inconel 601、Inconel 625、Inconel 718等）、ステライト合金（Stellite 6B、Stellite 1、Stellite 4、STELLITE 8、STELLITE 12、STELLITE 20等）、純金属（アルミニウム、銅、鉄等）、その他の金属（軸受鋼CGr15、チタン合金TC4、ハステロイC276等）、プラスチック（POM、PP、PA、BB、PEEK、PTFE等）、ガラス（光学ガラス等）。

セラミックボールは、精密軸受、医療機器、航空宇宙、自動車、および高温耐食性設備などにおいて広く使用されています。異なる素材で作られたセラミックボールは、硬度、密度、耐熱性、耐食性といった主要特性に大きな差異を示します。以下に、主流の4種類のセラミックボールについて、製品選定に役立つ各パラメータの比較表を示します。 | パラメータ | ジルコニアセラミックボール | アルミナセラミックボール | 炭化ケイ素セラミック | 硝化ケイ素セラミックボール | |------------|--------------------------|------------------------|---------------------|---------------------------| | 製品画像 | 乳白色／ベージュ色 | 高光沢で表面が非常に滑らか | 純白 | 黒みがかった灰色 | | 外観 | 滑らかな表面 | 均一で整った外観 | 非常に高い表面仕上げ | 粗い表面 | | 硬さ | 硬質 | 硬質 | 硬質 | 硬質 | | 表面状態 | 整然として均一な外観 | マット仕上げ | 密度が高く緻密な構造 | マット仕上げ | | 色合い | 白色 | 白色 | 白色 | 黒みがかった灰色 | | 密度（g/cm³） | 6.05 | 3.9 | 3.2 | 3.25 | | ロックウェル硬さ（HRA） | 89～90 | 88～89 | 92～93 | 91～92 | | 耐熱温度（℃） | 1000℃ | 1200℃ | 1600℃ | 1300℃ | | 圧縮強度（MPa） | 2000 | 1800 | 2200 | 2100 | | 耐食性 | 酸・アルカリに耐性 | 耐食性 | 優れた耐老化性 | 弱酸・弱アルカリに耐性 | | 使用上の注意 | 強酸・強アルカリ環境では慎重に使用 | 強酸・強アルカリ環境での使用には注意が必要 | 強酸・強アルカリに極めて高い耐性 | 強酸・強アルカリに耐性があり、溶剤による侵食にも強い | | 電気絶縁性 | 高い絶縁性 | 絶縁性 | 超高絶縁性 | 安定した電気的性能 | | 主な特徴 | 優れた靭性、欠けや割れに強い | 硬くて摩耗に強く静粛性が高い | 高精度でコストパフォーマンス良好 | 均一な組織と優れた汎用性 | | 特筆すべき点 | 超硬質で超耐摩耗性、超高温耐性 | 耐食性と耐熱性に優れる | 耐食性が特に優れている | 摩擦係数が低く、高温・高圧下でも安定 | | 主な用途 | 精密軸受、医療機器、食品加工機械、バルブ・バルブコア、電子機器、精密計測機器、高速伝達部品 | 化学プラント、研磨・研削、ハードウェア部品、シール、標準軸受、家電部品、水処理設備 | 高温設備、化学耐食設備、航空宇宙、冶金機械、高圧耐摩耗部品、極限環境向け部品 | 高速精密軸受、風力発電設備、自動車精密部品、航空宇宙、高温動力設備 | | ご注文に関する詳細はカスタマーサービスまでお問い合わせください。 | カスタムカラーのご要望がある場合は、指定寸法・公差・使用条件をご提示ください。当社の技術チームがお客様に最適なソリューションをご提案いたします。図面や仕様書をお送りいただければ、無料でお見積もりをご提供いたします。 |.

2016年に設立され、浙江省嘉興市に本社を置くJNE新材科技有限公司は、ハイエンドな新素材の研究開発・スマート製造・産業化を専門とする国家級ハイテク企業です。同社は高精度球体、超精密軸受部品、高精度ボールバルブシート、ならびに各種異形状カスタム精密部品を得意としています。製品にはジルコニア、窒化ケイ素、炭化ケイ素、アルミナ、超硬合金、非磁性合金、高密度合金、ステンレス鋼、サファイア、プラスチック、ガラスなど、多種多様な高品質原材料を使用しています。製品ラインナップは先進セラミックス、超硬合金、特殊用途合金、精密金属、プラスチックなど、全シリーズにわたります。幅広い規格と卓越した精度により、各種ハイエンド用途に求められる厳しい運用基準を満たしています。経営面では、明確な社内組織体制と整備されたマネジメントシステムを備えた、標準化・体系化・精緻化された運営モデルを採用しています。ISO 9001:2015品質マネジメントシステム、ISO 14001:2015環境マネジメントシステム、ISO 45001:2018労働安全衛生マネジメントシステムの認証を取得しています。技術面では、常にイノベーション主導の発展戦略を堅持し、独自のコア技術の研究開発と知的財産の戦略的保護を重視しています。これまでに計35件の独自特許を取得しており、そのうち発明特許が10件、実用新案特許が25件です。豊富な特許技術ポートフォリオを活かし、強固な技術的競争優位を確立するとともに、製品の高精度化・高性能化・高付加価値化を継続的に推進し、業界におけるトップランナーとしての地位を着実に確立しています。生産面では、総面積3,000平方メートルを超える高水準の近代的生産施設を保有しています。標準化されたクリーンルーム、先進的なスマート加工設備、そして高精度な物理・化学試験機器を完備し、大規模量産能力と柔軟でカスタマイズ可能な研究開発能力を両立させることで、十分な生産キャパシティと納期厳守を確保しています。同時に、ワンストップのエンドツーエンド型サービス体制を構築し、ソリューション設計、試作開発、量産、技術統合、アフターサービスに至るまで、きめ細やかな総合サービスを提供することで、個々の顧客ニーズに柔軟に対応しています。製品は、航空宇宙、ハイエンド医療精密機器、半導体流体装置、新エネルギー機器、5G通信、ハイエンド油圧・空気圧機器、精密計測機器、産業用流体バルブ、スマート自動化設備など、数多くのハイテク・最先端分野で広く活用されています。高い評価により、多くの業界関係者から深い信頼を得ており、販売ネットワークは国内全域に広がり、国内外の市場へ製品を輸出しています。 JNEの社員一同は、「卓越した品質、献身的な取り組み、並外れた卓越性」という当社の核心的文化価値観を揺るぎなく守り続けています。職人精神、誠実さ、実践的な前進という創業理念を貫き、厳格な基準に基づいて高品質な製品を磨き上げ、真心こめたサービスを通じて忠実な顧客基盤を築いてまいります。今後も、研究開発への投資を一層拡充し、技術革新と産業高度化に注力して、ハイエンド精密新素材のスマート製造における国内一流ブランドの構築を目指します。各界のパートナーの皆さまとともに力を合わせ、共に新たな産業機会を探求し、協働による新しい未来を切り拓いてまいります。.