Overview
Hardened screws are precision-engineered fasteners that undergo thermal or chemical treatments to achieve superior hardness and strength compared to standard screws. They are critical in applications where mechanical stress, vibration, or heavy loads could compromise the integrity of conventional fasteners. The hardening process typically involves quenching and tempering to balance hardness with toughness, reducing brittleness. These screws are commonly graded under systems like ISO or ASTM (e.g., Grade 8.8 or 12.9) to indicate their mechanical properties, ensuring reliability in industrial settings.
Structure and Working Principle
Hardened screws feature a threaded shank and head (e.g., hex, Phillips) designed to distribute clamping force evenly. The threads are often rolled post-hardening to maintain precision without cracking. Their working principle relies on the combination of high tensile strength (often exceeding 150,000 psi) and shear resistance. The hardened surface layer (achieved through case hardening or through-hardening) resists wear, while the core retains some elasticity to absorb dynamic loads.
Key Features
1. **Enhanced Durability**: Heat treatment increases surface hardness (up to 45 HRC or higher), reducing thread deformation under pressure. 2. **Corrosion Options**: Stainless steel variants (e.g., A2/A4) offer rust resistance, while carbon steel screws may require plating (e.g., zinc, black oxide). 3. **Precision Threads**: Uniform threading ensures consistent torque performance and reduces the risk of stripping. For extreme environments, secondary coatings like Dacromet or geometric locking features (e.g., Nord-Lock washers) may be specified.
Application Areas
1. **Automotive**: Engine components, suspension systems, and brake assemblies where vibration resistance is critical. 2. **Industrial Machinery**: Heavy-duty equipment like presses, conveyors, and hydraulic systems. 3. **Construction**: Structural steel connections and high-stress joints in bridges or towers. In aerospace and defense, specialized alloys (e.g., A286) are used for their high-temperature performance.
Maintenance and Precautions
Regular inspections for thread wear or elongation are recommended, especially in cyclic loading environments. Lubrication (e.g., anti-seize compounds) can prevent galling in stainless steel screws. Avoid using hardened screws with softer materials (e.g., aluminum) without thread inserts, as the hardness mismatch may cause stripping. Always adhere to manufacturer torque specifications to prevent overloading.
B2B Procurement Guide
1. **Volume Discounts**: Bulk purchases (1,000+ units) often reduce costs by 15–30%. 2. **Certifications**: Require mill test reports (MTRs) or ISO 898-1 compliance for critical applications. 3. **Customization**: Suppliers may offer tailored lengths, head styles, or drive types (e.g., Torx for high-torque needs). Leading manufacturers include ARP, Bossard, and Fastenal. For niche applications (e.g., offshore), verify compliance with standards like NACE MR0175.
Related Manufacturers
- 主营：组合螺栓、外六角螺栓、外六角组合件、外六角组合螺丝、外六角组合套装
- 主营：六角螺丝、外六角螺钉
- 主营：不锈钢螺栓、不锈钢螺母、膨胀螺栓、沉头钻尾螺丝、光伏支架、钻尾丝、高强度螺栓、热镀锌螺栓、全螺纹丝杆
- 主营：建筑螺栓、地脚螺栓、不锈钢螺栓、沉头钻尾螺丝、建筑配件
- 主营：铝合金铆钉、六角螺栓、六角螺母、圆柱头螺丝、内六角螺丝、沉头螺丝、非标螺丝、自攻螺丝、T型螺丝、钻尾螺丝、四方螺栓、方螺母、十字自攻、圆头螺钉、平垫、弹垫、梅花螺钉、紧定、活节螺栓、圆柱销、铆螺母、挡圈、牙条、牙棒
- 主营：异型螺丝、鹅蛋螺栓、外六角螺母、钻尾自攻丝
- 主营：铜销轴、纯铜铆钉、装饰螺母、铜螺丝、螺丝钉、平头螺丝、手拧螺丝、十字螺丝、法兰螺丝、自锁螺丝、六角螺栓、自攻螺钉、十字螺钉、燕尾螺钉、接线螺柱、非标车件、英制螺栓、尼龙垫片、铜车配件、非标铜件、自动车床、防盗螺栓、铜件定制、铜螺母、注塑螺母
- 主营：烧烤架、热风枪、圆锯片、螺丝、开石器、角磨机、石匠凿、缝纫机、电磨机、电机轴、反十字、烧烤炉、钨钢凿、烧烤碳、下水道、烧水杯、冲击钻、置物架、钻电池、拆焊台、内六角、润滑油、长六角、增氧泵、汽车腰、显示器
- 主营：倒角器、扳手架、调压阀、梅花螺丝、打结刀、磨光机、电磁阀、测量仪、切管器、搅拌机、覆膜机、角磨机、电动机、打磨机、测亩仪、风速仪、割纱刀、热熔胶、减压阀、轴承座、铁皮剪、电链锯、干磨机、高速电机、电动球阀、铜管割刀
- 主营：304不锈钢螺栓、2205不锈钢螺栓、310S不锈钢螺栓、304不锈钢螺丝、2205不锈钢螺丝、310S不锈钢螺丝、316不锈钢螺丝、热镀锌螺丝、达克罗螺丝、316不锈钢螺栓、304不锈钢螺母、热镀锌螺栓
- 主营：不锈钢螺栓、不锈钢索具、不锈钢螺母、合螺丝、螺丝帽、不锈钢钻尾钉、不锈钢膨胀螺栓、平键销、轴销钉、收紧器、骑马卡、接地线、避雷针、支撑架、固定销、护栏母、斜拉杆、套筒母、预埋件、圆螺母、扁螺母、靠背销、山形卡、定位销、球面垫
- 主营：抗震支架
- 主营：干壁钉、自攻钉、自攻螺钉、欧式螺丝、家具螺丝、自攻螺丝、甲板螺丝、纤维板螺丝、干墙螺钉、纤维板螺钉、号角头十字槽
- 主营：铆钉、非标铆钉、电脑非标铆钉、电脑螺丝螺母、电脑非标螺丝螺母、电子螺丝螺母、非标不锈钢304螺丝、非标不锈钢316螺丝、塑胶弹簧螺丝、电器螺丝螺母、手机螺丝、散热器螺丝弹簧O扣、散热器螺丝、塔簧螺丝、不锈钢304铆钉、家具紧固件、紧固件定制、非标PET垫片定制、电器紧固件、电器弹簧、弹簧
- 主营：羊眼镙丝、装饰画挂钩、包塑杯钩、杯钩螺丝、加强挂钩美式挂钩、羊眼钉羊眼螺丝、螺丝钩、螺丝钉 钉子、吊环螺丝、浸塑杯钩、七字钩、L直角钩、灯钩、塑料膨胀塑料盒、兰花夹吊钩、金属挂钩、羊眼钉钩、直角L钩、三角挂钩、不锈钢弹簧钩、兰花夹、花篮挂钩、金色相框配件、无痕挂钩铜帽挂钩、不锈钢羊眼钉、问号杯子挂钩、五金挂钩配件