Precision Stainless Steel
Valves & Components
for Critical Industries.
From high-purity pharmaceutical valves to high-pressure pipeline fittings — Zetu Machinery casts, forges, machines and finishes precision metal components for OEM buyers worldwide.
“Creating value that increases customers' competitiveness.”
A focused specialist — not a general trading company.
Valve & Precision Specialists
Stainless steel valves and precision components are our core — not a sideline. Silica-sol investment casting, forging and machining under one roof.
Built for Critical Industries
Pharmaceutical, oil & gas, and chemical buyers trust us with pressure-rated, high-purity parts. ISO 9001 and PED certified.
Documented Quality
98%+ first-pass yield. CMM verification, tensile and hardness testing, optical projection — with material and inspection reports on request.
Proven Export Partner
90% of what we make ships to the US and EU. 20+ years of international trade experience and an English-speaking technical team.
Meet Olive Zhang.
Senior Account Manager · 20+ years in valves & precision manufacturing
“Care for details, integrity in delivery — that's how we keep customers, not process.”
Five core processes. One accountable partner.
Casting Services
Silica-sol investment casting, water-glass casting, sand casting, and aluminum / zinc die casting — from drawing to machined-ready part.
- • Silica-sol (lost-wax) investment casting
- • Water-glass & coated-sand casting
- • Stainless steel 304 / 304L / 316 / 316L
- • Ductile iron, grey iron, copper alloys
CNC Machining
Precision CNC milling and turning on 32 machines — tolerance to ±0.01 mm (0.0004 in), surface finish to Ra 0.4.
- • 13 CNC machining centers
- • 16 precision CNC lathes
- • 3 imported high-precision CNC machines
- • Tolerance to ±0.01 mm (0.0004 in)
Forging Services
Open-die and closed-die forging from 120T to 2,000T — stainless steel, aluminum, carbon steel and copper.
- • 120T – 2,000T press range
- • Stainless steel & carbon steel forging
- • Aluminum & copper forging
- • Heat treatment & post-machining
Stamping & Fabrication
Metal stamping, welding, and fabricated assemblies in stainless steel, mild steel and aluminum.
- • Metal stamping & pressing
- • MIG / TIG / spot welding
- • Sheet metal fabrication
- • Stainless, mild steel & aluminum
Finishing & Coating
Powder coating, wet paint, electroplating, electrophoresis (e-coat) and polishing — protected, color-matched parts.
- • Powder coating & wet paint
- • Electroplating
- • Electrophoresis (e-coat)
- • Polishing & surface refinement
Assembly & Logistics
From single component to ready-to-ship sub-assembly — packaged, palletized and DDP-delivered.
- • Welding & sub-assembly
- • Custom packaging & labeling
- • EXW / FOB / CIF / DDP
- • Worldwide shipping support
Precision valves, fittings & engineered components.
High-Pressure Valve Fittings
A105 carbon steel
- • Sizes 1/2" – 2"
- • Surface Ra 0.8
- • Bore Ra 0.4
- • Pressure-rated
Application: Oil, gas & petrochemical pipelines
Iron & Steel Castings
Steel · Ductile iron · Grey iron · Copper
- • Silica-sol & water-glass investment casting
- • Coated-sand & clay-sand casting
- • Machined-ready blanks
Application: Spiral castings, pump bodies, structural cast parts
Lost-Wax & Sand Casting
Stainless · Carbon steel · Iron · Brass
- • Silica-sol investment (lost-wax) casting
- • Coated-sand & clay-sand casting
- • Weight 0.05 – 80 kg per piece
- • As-cast surface Ra 3.2 – 6.3
Application: Pump bodies, valve housings, structural components
Forged Components
Stainless steel · Aluminum · Carbon steel · Copper
- • 120T – 2,000T press range
- • Open-die & closed-die
- • Heat treatment included
Application: High-strength structural & pressure parts
Aluminum Forgings
Aluminum alloy
- • Closed-die & open-die forging
- • Heat treatment included
- • Machined finish on request
Application: Flanges, discs, hubs and rotating structural parts
Aluminum Die Castings
Aluminum alloy
- • 180T – 1,800T machine range
- • Thin-wall & cosmetic surfaces
- • High repeatability
Application: Enclosures, heat sinks, automotive parts
Aluminum Profiles & Extrusions
Aluminum alloy
- • Bars & plates
- • Custom extruded sections
- • Machined to drawing
Application: Machined aluminum sub-assemblies and custom components
Custom Precision Machined Parts
Steel · Stainless · Aluminum · Aluminum bronze
- • Tolerance to ±0.01 mm
- • Surface finish to Ra 0.4
- • Build-to-print / build-to-sample
Application: Custom precision components across industries
Stainless Steel Precision Machining
304 · 304L · 316 · 316L · 17-4PH stainless
- • 5-axis CNC machining
- • Tolerance to ±0.005 mm
- • Surface Ra 0.4 / bore Ra 0.2
- • Bar, casting & forging blanks accepted
Application: Valve trim, medical components, food-grade fittings
Sheet Metal & Stamping
Stainless · Carbon steel · Galvanized · Aluminum
- • Laser cutting, bending, welding, stamping
- • Sheet thickness 0.5 – 6 mm
- • Progressive die & deep-draw
- • Powder-coat / passivation finish
Application: Enclosures, brackets, panels, equipment cabinets
Trusted by buyers across demanding industries.
Pharmaceutical & Hygienic
High-purity F316L valves and fittings with polished Ra 0.4 bores for sterile process systems.
Our flagship segment. Forged high-purity stainless steel valves in A182-F316L, with controlled ferrite and sulfur content and hygienic surface finishes — built for pharmaceutical process equipment.
Oil, Gas & Petrochemical
A105 high-pressure valve fittings and pressure-rated components for pipelines.
High-pressure valve fittings in A105 and stainless grades, finished to Ra 0.4 bore — engineered for petroleum, gas and petrochemical pipeline service.
Chemical Processing
Corrosion-resistant stainless steel valve bodies, pumps and fluid-control parts.
304 / 316 stainless steel castings, forgings and machined components selected for corrosion resistance in chemical process environments.
Power & Energy
Cast and machined components for power generation and energy infrastructure.
Iron, steel and aluminum castings plus precision-machined parts for power generation, electrical equipment and energy infrastructure.
Automotive
Die-cast, forged and machined components for automotive systems.
Aluminum die castings, forgings and machined parts supporting automotive component programs.
Marine & Heavy Industry
Castings, forgings and fittings for shipbuilding, railway, mining and food equipment.
Robust castings, forgings and machined components serving shipbuilding, railway, mining and food-processing equipment.
A 3,000 m² plant. 32 CNC machines. Round-the-clock production.
Machining Floor
- • 13 CNC machining centers
- • 16 precision CNC lathes
- • 3 imported high-precision CNC machines
- • 3-shift, 24-hour production
Casting & Forging
- • Silica-sol & water-glass investment casting
- • Ductile & grey iron casting lines
- • Aluminum / zinc die casting 180T–1,800T
- • Forging 120T–2,000T
Quality Lab
- • CMM / three-coordinate measurement
- • Tensile strength & hardness testers
- • Optical projector & roughness testing
- • 8 dedicated QC staff
Strive for excellence — refine every detail.
ISO 9001 & PED certified · Material and inspection reports on request.
20+ years of casting, forging & machining expertise.
Ningbo Zetu Machinery Co., Ltd. is a manufacturer of precision stainless steel valves, fittings and engineered metal components — serving pharmaceutical, oil & gas, chemical, power and industrial customers worldwide.
Our team has built precision parts together since 2008, growing a Ningbo workshop into a 3,000 m² plant with 70+ staff and round-the-clock production. Founding Zetu lets us serve global OEM buyers directly — with faster engineering response and transparent pricing.
Our promise: we only ship products our customers are satisfied with.
“Creating value that increases customers' competitiveness.”
Read our full story →- Legal Entity
- Ningbo Zetu Machinery Co., Ltd.
- Heritage
- Since 2008
- Facility
- 3,000 m² plant
- Team
- 70+ skilled staff
- Certifications
- ISO 9001 · PED
- Headquarters
- Yinzhou, Ningbo, China
20+ years of steady growth.
The journey begins
Our team's manufacturing operation is founded in Ningbo as Zeyang Machinery, with 5 people and a focus on precision metal parts.
Scaling up
Annual output passes ¥10M; the team grows to 30 as stainless steel valve work expands.
Industrial capacity
Output passes ¥25M with 55 staff; 24-hour three-shift production established.
70-strong team
Output passes ¥30M; the team reaches 70, including senior engineers and a dedicated QC group.
Ningbo Zetu Machinery founded
A new chapter — Ningbo Zetu Machinery Co., Ltd. is established to serve global OEM buyers directly, carrying forward 20+ years of casting, forging and machining expertise.
Looking ahead
Focused on stainless steel products and high-quality valves, targeting US$10–15M annual output.
Three kinds of value.
Our culture rests on a simple idea — good manufacturing creates value in three directions at once.
Create value for customers
Every part we make is judged by one question — does it make our customer more competitive?
Share value with our team
Skilled, motivated people build better parts. We grow with the people who build them.
Contribute value to society
Responsible, quality manufacturing that earns its place in the global supply chain.
From your drawing to series production.
A clear, repeatable workflow — accountability at every stage. Olive owns the handover from inquiry to shipment.
Drawing Review
DFM feedback on your 2D / 3D file within 24 hours.
Tooling & Sampling
Rapid mold build, first article and approval before mass run.
First-Article QC
Dimensional + visual inspection report — your sign-off, your standard.
Series Production
Scheduled batches shipped with full QC documents and material certs.
Excellence, refined into every detail.
Quality is managed by SOP — first-article approval, in-process checks, and final inspection — backed by an ISO 9001 and PED certified system and a dedicated quality lab.
Send your drawing.
Tell us about the part — material, tolerance, finish, volume. Olive will respond with DFM feedback, pricing, and lead time within one business day.
Room 1703-1, No.456 Taikang Middle Road, Yinzhou District, Ningbo, Zhejiang, China