JIS Standard SKD61 Steel Nitrided Straight Ejector Sleeves

This nitrided ejector sleeve variant is used in straight ejector sleeve components for injection molds where repeatable alignment between the sleeve and ejector rod is critical. In automotive connector and housing molds, the controlled bore provides stable guidance as ejector pins/rods travel under high cycle loads, helping maintain smooth ejection and reducing risk of sticking.

It is also suited for appliance and consumer electronics housings that require consistent ejection stroke across multiple cavities. The nitrided surface and SKD61 steel base improve resistance to fretting and sliding wear, supporting long-term dimensional stability.

• Single-sleeve design simplifies assembly and standardizes fit in ejector arrangements.
• Concentricity 0.06 supports reliable alignment in the sleeve-to-shaft relationship.
• H7 inner diameter tolerance helps achieve the designed clearance for stable motion.

JIS standard SKD61 steel (commonly associated with H13-class hot-work tool steels) is selected here to balance toughness for mold operation with adequate wear performance for ejector sliding interfaces. The sleeve is supplied with a nitrided surface treatment, which forms a hard, wear-resistant case that improves resistance to galling and surface fatigue.

Typical SKD61 nitrided ejector applications target a hardness in the mid-to-high HRC range after appropriate heat treatment, but the exact HRC value depends on the supplier’s process window and nitriding depth. The trade-off is that nitriding primarily increases surface hardness and wear resistance; the core toughness remains important to avoid cracking under intermittent shock loads.

• Before/after state: base material is SKD61, then nitrided for enhanced surface performance.
• Wear vs. toughness: harder surface with preserved core strength for reliable ejection.

Select the sleeve using the specified shaft diameter (D/P) range and match the hole diameter (V) to the ejector or guiding geometry in your mold. For this product, D/P = 4 ~ 20 mm and V = 0.5 ~ 12 mm, so your ejector rod/shaft and the related locating feature should fall within these limits.

Then choose the required L (length) from 100 ~ 225 mm to cover the full guiding length needed for the stroke and expected side load. Confirm the sleeve-to-rod clearance by using the inner diameter tolerance H7 and the provided shaft diameter tolerance options (-0.01/-0.02 or -0.01/-0.03), which affect fit tightness.

• Use the head thickness as per JIS options: 6 mm or 8 mm.
• Maintain consistent concentricity (0.06) by selecting the correct bore/shaft pairing rather than forcing assembly.