Titanium Alloy Lens Gasket Sealing Joints

TC4 (Ti-6Al-4V) lens gasket sealing joints in DN4 to DN25, PN160 to PN420, machined and 100 percent helium leak tested by KGL. Quotes within 24 hours, no MOQ.

Semiconductor & Optics

KGL machines TC4 (Ti-6Al-4V, ASTM B348 Grade 5) lens gasket sealing joints for semiconductor process gas lines, vacuum foreline isolation, offshore seawater service, and chemical feed duty to 600 degrees C, covering DN4 to DN25 bore sizes at PN160 to PN420 with every joint helium leak tested before shipment.

Custom to drawing±0.005 mm standard toleranceQuote in 24 hNo MOQISO 9001 · ISO 13485 · AS9100D

Request a Quote for This Part

Or email drawings to kgl@kglmfc.com

Relevant Capabilities

Turn-Mill Machining CNC Turning

Materials

Titanium

Key Specifications

Parameter	KGL Capability
Material	TC4 titanium (Ti-6Al-4V, ASTM B348 Grade 5), annealed
Mechanical properties	Tensile strength at or above 950 MPa, hardness approx. 36 HRC
Bore range	DN4 to DN25 (1/4" to 1")
Pressure class	PN160 to PN420 (Class 900 to 2500)
Connections	NPT or BSPP 1/4" to 1"; flanges per ASME B16.5 or GB/T 9115
Seal face finish	Ra at or below 0.2 um (sphere), Ra at or below 0.4 um (cone)
Fit accuracy	IT6
Profile accuracy	Plus or minus 0.002 mm after WEDM-LS finishing
Sealing test	GB/T 13927-2008 Class A, helium leak rate at or below 1 × 10⁻⁹ Pa·m³/s
Shell test	API 598, 1.5 times rated pressure, 3 minute hold, no leakage
Inspection	100 percent tested before shipment
Tolerance	±0.005 mm standard on metals, engineering plastics, and carbon fiber composite
Process	5-axis CNC milling, 3+2 milling, CNC turning, EDM as required
Certifications	ISO 9001:2015, ISO 13485:2016, AS9100D
Capacity	100+ CNC machines including 11 five-axis centers
MOQ	No MOQ; 1-piece prototypes supported
Quote	Within 24 hours for complete 2D/3D files

About This Part

The lens gasket sealing joint closes a pipeline through line contact between a spherical and a conical face. Under bolt preload this line contact concentrates stress into a narrow metal sealing ring, so the joint tightens itself further as system pressure rises. KGL machines these joints from TC4 titanium, the Chinese designation for Ti-6Al-4V (ASTM B348 Grade 5), supplied in the annealed condition per ANSI/ASTM B348 with a tensile strength of at least 950 MPa and a hardness near 36 HRC. Pure titanium TA2 was rejected for this duty: at 400 to 550 MPa it cannot carry the face loads of high pressure sealing. Compared with the AISI 304 stainless version, TC4 extends the operating window from neutral media at up to 400 degrees C to chloride bearing media, seawater, and wet chlorine at up to 600 degrees C, while the 114 GPa elastic modulus gives the faces enough elastic recovery to keep contact under pressure and thermal cycling.

The seal faces are cut on a MAZAK INTEGREX i-250H turn-mill center, which roughs and finish turns the sphere and cone to a profile accuracy of plus or minus 0.005 mm. Slow wire EDM (WEDM-LS) then trims the profile to plus or minus 0.002 mm at Ra 0.4 um, and lapping and polishing bring the spherical face to Ra 0.2 um. Every dimension is verified before assembly: a Zeiss CAPTUM CMM scans the face profile at a 0.05 mm point pitch with 0.0015 mm measurement uncertainty, a Talyrond roundness tester checks the sphere, and an optical projector measures the sealing line contact width.

Leak tightness is proven, not assumed. Each joint passes a helium mass spectrometer test to GB/T 13927-2008 Class A with a leak rate at or below 1 × 10⁻⁹ Pa·m³/s, plus an API 598 shell hydrostatic test at 1.5 times rated pressure held for 3 minutes. 100 percent of production is tested before shipment.

Why Machine It at KGL

Five-Axis Fleet

100+ CNC machines including 11 five-axis centers run complex geometry in single setups, so tolerances do not stack up across refixturing.

Verified Accuracy

±0.005 mm standard on metals, plastics, and carbon fiber composite, verified on Hexagon and Zeiss CMMs (0.0015 mm accuracy).

Fast Prototypes

Engineering feedback with every quotation; prototype parts typically machined in 15 to 25 days.

One Supplier, End to End

Material sourcing, machining, heat treatment coordination, finishing, CMM inspection and export packaging under one roof.

Part-Specific Advantages

TC4 titanium for aggressive duty. Annealed Ti-6Al-4V per ASTM B348 Grade 5, tensile strength at or above 950 MPa, hardness near 36 HRC, continuous service to 600 degrees C, and chloride resistance that outlasts 316L by 5 to 8 times in seawater.
Self-energizing line contact seal. The spherical and conical faces form a metal sealing ring under bolt preload, so sealing force grows with system pressure; faces are finished to Ra 0.2 um on the sphere and Ra 0.4 um on the cone with IT6 fit accuracy.
Turn-mill plus slow wire EDM route. MAZAK INTEGREX i-250H turning holds plus or minus 0.005 mm on the profile, then WEDM-LS trims critical faces to plus or minus 0.002 mm before lapping, keeping geometry stable on the hard titanium alloy.
Measured, not estimated, geometry. Zeiss CAPTUM CMM profile scanning at 0.05 mm pitch with 0.0015 mm uncertainty, Talyrond roundness verification of the sphere, and optical projection of the contact width give documented face quality on every batch.
Rated for high pressure lines. DN4 to DN25 bores (1/4 inch to 1 inch) at PN160 to PN420 (Class 900 to 2500), with NPT or BSPP threads and flanges per ASME B16.5 or GB/T 9115, helium leak tested to 1 × 10⁻⁹ Pa·m³/s.

Typical Applications

Semiconductor process gas delivery. High purity chlorine and hydrogen chloride lines, where TC4 resists chloride attack better than 316L and keeps the gas path metal sealed.
Vacuum foreline isolation. Low outgassing titanium construction supports isolation valves on forelines down to an ultimate vacuum of 1 × 10⁻⁷ Pa.
Offshore seawater systems. High pressure seawater piping where TC4 service life runs 5 to 8 times longer than 316L in the same line.
Chemical reactor feed service. Feed and dosing lines at up to 600 degrees C and PN420, where strength retention exceeds AISI 304 and elastomer seals are not an option.

Commercial Terms

Commercial	Detail
MOQ	No MOQ; 1-piece prototype supported
Quote	Within 24 hours for complete 2D/3D files
Terms	EXW / FOB Shenzhen
Certifications	ISO 9001:2015, AS9100D, ISO 13485:2016
Packaging	Individual bubble wrap, export wooden case

Common Questions

Why TC4 instead of TA2 or stainless steel for this joint?

TA2 is commercially pure titanium with a tensile strength of only 400 to 550 MPa, which cannot carry the contact loads of a high pressure metal seal. AISI 304 covers neutral and mildly corrosive media up to about 400 degrees C. TC4 combines a tensile strength of 950 MPa or more with chloride resistance and continuous service to 600 degrees C, which is why it is the default choice for chlorine, seawater, and hot chemical lines.

What sizes and pressure ratings can you supply?

Standard coverage is DN4 to DN25 (1/4 inch to 1 inch) at PN160 to PN420 (Class 900 to 2500), with NPT or BSPP threads from 1/4 inch to 1 inch. Flanged ends follow ASME B16.5 or GB/T 9115. Joints outside these ranges are quoted per drawing.

How do you verify the sealing surfaces before shipment?

A Zeiss CAPTUM CMM scans the sphere and cone profile at a 0.05 mm point pitch with 0.0015 mm measurement uncertainty, a Talyrond roundness tester verifies the spherical face, and an optical projector measures the sealing line contact width. Face finish targets are Ra 0.2 um on the sphere and Ra 0.4 um on the cone.

How is leak tightness proven?

Every joint is helium mass spectrometer tested to GB/T 13927-2008 Class A with a leak rate at or below 1 × 10⁻⁹ Pa·m³/s, and the shell passes an API 598 hydrostatic test at 1.5 times rated pressure held for 3 minutes. 100 percent of production is tested, not sample batches.

Do you accept prototype quantities?

Yes. There is no minimum order quantity and 1-piece sampling is supported. Send a complete 2D or 3D file and you will receive a quote within 24 hours.