Pump & Valve Fasteners | Casing Studs, DIN975 Double-Ends and Overhaul Spare Kits
Fastening for pump casing flanges, valve covers, line flanges and base anchors: DIN975/976 studs with DIN934 nuts for easy teardown, 8.8/10.9 carbon steel or A2/A4 stainless by medium and environment; bolts + nuts + washers kitted in one container to cut site shortages and grade mixing.
Key Technical Challenges
Frequent overhaul: studs gall and teardown damages threads, spare burn-out exceeds budget
Humid halls and outdoor skid pumps outgrow plain electro-zinc (48-240 h NSS)
Uneven casing preload causes internal leakage; high torque scatter batches are the hidden risk
Many small SKU orders arrive incomplete - one missing size halts the crew
Xin Rui Da Fastener Solutions
Studs and nuts supplied as matched sets (grade-8 nut on 8.8 stud) so the internal thread never fails first
304/A2 for humid rooms; step to 316/A4 (PREN 24-26) for coastal pump stations
Flange hardware gives a large stable bearing face with low torque scatter; M6-M24 torque chart included
Mixed-container consolidation, VCI bags and IPPC crates; overhaul kits bagged and labelled per BOM
Technical Parameters
| Common Items | DIN 975/976 studs · DIN 933/931 · DIN 934 |
| Grades | 8.8 / 10.9 · A2-70 / A4-80 |
| Moist Environment | 304 (inland) / 316 (coastal) |
| Kitting | Bolt + nut + washer sets, BOM bagging |
| Trial MOQ | 500 pcs per model |
Frequently Asked Questions
Follow the flange system: metric flanges take DIN/GB studs (e.g. 35CrMo, DIN975/976 form); ASME B16.5 flanges take ASTM A193 B7 with A194 2H nuts. Diameter-strength relationships differ between systems - do not interchange them.
Dry rooms run on zinc-plated 8.8; humid halls call for 304 (A2-70); coasts or de-icing salt zones need 316 (A4-80) or Dacromet carbon parts. Stainless still ships with VCI sea protection.
Repeated teardown changes thread friction and profile; treat high-strength studs in critical pump trains as single-use or re-verify against the torque chart each reassembly, with anti-seize applied to ease the next removal.
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