JIS Standard SKH51 Steel Gas Release Rectangular Ejector Pins

These gas release rectangular ejector pins are used in injection mold tooling where consistent cavity venting is needed to stabilize ejection and reduce cycle-related defects. The gas-release geometry supports efficient mold exhaust, helping maintain uniform venting so parts eject more smoothly during high-repeat production.

• Automotive interior and connector molds: Ideal for applications that require reliable ejection of flat or thin-walled features. The flat-sided head assists precise positioning and alignment in the ejector plate, supporting stable motion over long runs.
• Electronics housings and light assembly parts: Commonly used where trapped air can cause short shots or surface blemishes. This SKH51 variant is suited for precision venting and wear-resistant performance in production molds.
• Precision consumer product molds: Helps improve exhaust consistency for repeatable part release when ejector alignment must stay tight across many cycles.

Because the flat-sided head supports repeatable location and the gas release design promotes stable venting, this variant is well suited for molds requiring both alignment control and consistent exhaust.

The pins are manufactured from JIS Standard SKH51 steel, selected for its balanced performance in tool components exposed to wear and repeated contact. SKH51 is commonly considered comparable to AISI M2 high-speed steel, offering strong hot hardness and good wear resistance for ejector features.

• Heat treatment: quench-hardened construction (as specified), typically followed by tempering to control brittleness.
• Hardness: not provided in the input data; hardness should be verified from the manufacturer’s mill/test certificates for the exact lot and heat treatment condition.
• Wear vs. toughness trade-off: hard, wear-focused treatments improve abrasion resistance at the tip and contact areas, while tempering is used to retain adequate toughness for cyclic ejection loads.

If you compare against lower-alloy steels used for simpler ejector pins, SKH51 generally prioritizes wear resistance for long-life precision ejection, while requiring careful handling during machining to maintain dimensional stability.

Select the ejector pin dimensions to match both the shaft clearance in the ejector housing and the support/locating requirements of the ejector plate.

• Shaft diameter (D): choose from 1.5 to 15 mm based on the receiving bore/guiding feature. Use the specified D to ensure proper clearance and alignment repeatability.
• Tip geometry: select P (1 to 3.5 mm) and W (1 to 3.5 mm) to achieve the required contact footprint and gas-release effectiveness without interference.
• Length (L): available in multiple ranges (e.g., 40–250, 40–300, 50–300, 40–350, 50–350 mm)—pick the L that ensures sufficient stroke engagement in your mold stack-up.
• Head thickness (T4/JIS variants): options include 4 mm (T4/4), 4 mm (JIS), 6 mm (JIS), 8 mm (JIS). Match to your ejector plate thickness and stop/shoulder design.

Also verify Dimension N (23 to 40 mm), which affects locating position. For tight ejector alignment, maintain consistent bore tolerances and allow for thermal expansion and deflection based on your mold materials and operating temperature.