Product Summary

لونجزي Cross Recessed Countersunk Head Self-Tapping Screws (also known as Phillips Flat Head Sheet Metal Screws) are precision-engineered fasteners manufactured to DIN 7982, ISO 7050,

و ASME B18.6.3 standards. Featuring a $90^\circ$ countersunk head and a Phillips (Cross) drive, these screws are designed to sit flush with the material surface. They are the industry standard for joining thin metal,

plastics, and wood where a smooth, snag-free finish is required alongside high-speed assembly.

• ✔ Flush Profile Finish: The countersunk head ensures the screw sits level with or below the surface, ideal for hinges, brackets, and decorative panels.

•  

• ✔ Rapid Installation: The Phillips drive is optimized for power drivers, providing centered engagement and reducing the risk of the bit slipping during high-speed production.

•  

• ✔ Material Versatility: Case-hardened threads allow the screw to form its own mating thread in a variety of substrates, from sheet metal to dense plastics.

Product Highlight: Engineered for high-speed assembly, لونجزي countersunk self-tapping screws offer a high-strength, flush-finish solution for modern industrial and consumer applications.

 

• Precision $90^\circ$ Head Angle – Guaranteed consistency for seamless seating in standard countersunk holes, preventing gaps or sharp edges.

•  

• Case-Hardened Durability – Heat-treated to ensure sharp threads can cut through structural aluminum and thin steel sheets without tip blunting.

•  

• Deep Cross Recess – Optimized Phillips drive depth prevents premature "cam-out," extending driver bit life and protecting the workpiece surface.

Technical Standard: Manufactured to strict international tolerances, ensuring 100% compatibility with standard driver bits and pre-drilled pilot holes across all property classes.

 

 

• Standards: DIN 7982, ISO 7050 (Metric) / ASME B18.6.3 (Inch)

•  

• Drive Type: Phillips (Cross Recess) / Pozidriv

•  

• Metric Size Range: ST2.2 to ST9.5 (Diameter 2.2mm - 9.5mm)

•  

• Inch Size Range: #2 to 3/8" (Diameter 0.086" - 0.375")

•  

• Length Options: 4.0 mm to 150 mm (1/8" to 6")

•  

• Point Styles: Type AB (Pointed), Type B (Blunt)

•  

• Material: Case-Hardened Carbon Steel / Stainless Steel A2, A4

 

Material & Mechanical Properties

• Engineering Note: Structural integrity depends on the correct property class. We offer a full material range to meet your specific tensile strength and ductility requirements.

• مادة	Surface Hardness	Core Hardness	Feature
  Carbon Steel	HV 450 min	HV 270 - 390	High Thread-Cutting Strength
  الفولاذ المقاوم للصدأ	A2 (304)	Work Hardened	General Corrosion Resistance
  الفولاذ المقاوم للصدأ	A4 (316)	Work Hardened	Acid & Marine Resistance

Dimensions & Size Conversion

• Metric to Inch Comparison: Use the table below to find the closest equivalent for your project requirements. Longze provides precision conversion to meet global engineering needs.

• Metric Size (ST)	Diameter (mm)	Nearest Inch Size	Diameter (inch)	Head Dia (dk)
  ST2.2	2.2 mm	#2	0.086"	4.3 mm
  ST2.9	2.9 mm	#4	0.112"	5.5 mm
  ST3.5	3.5 mm	#6	0.138"	6.8 mm
  ST4.2	4.2 mm	#8	0.164"	8.1 mm
  ST4.8	4.8 mm	#10	0.190"	9.5 mm
  ST5.5	5.5 mm	#12	0.216"	10.8 mm
  ST6.3	6.3 mm	1/4"	0.250"	12.4 mm

Surface Treatment

• Procurement Guide: Surface finish determines service life. Longze provides specialized coatings to ensure maximum corrosion resistance and aesthetic consistency for any environment.

• Coating	Salt Spray	Appearance	بيئة
  Zinc Plated	72 - 144h	Silver / Blue	Indoor / General Hardware
  Black Oxide	24 - 48h	Matte Black	Electronics / Interior Trim
  Nickel Plated	48 - 96h	Bright Silver	Decorative Furniture
  Passivated	1000h+	Natural SS	Marine / Medical (SS)