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Molybdenum Fasteners

Molybdenum fasteners possesses a very high melting point of 2620°C, a low coefficient of thermal expansion and a high level of thermal conductivity. Because molybdenum fasteners have the ability to withstand extremely high temperatures without changing shape, expanding or softening significantly, they are ideal for high strength / high temperature applications that are shielded from oxygen. Exposing molybdenum fastener to oxygen above 600°C will cause them to readily oxidize.

RAYCHIN SPECIALTY METALS FASTENERS: BOLTS, NUTS, SCREWS, WASHERS, STUDS, THREADED RODS, U-BOLT, J-BOLTS

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Molybdenum fasteners find their way into high temperature vacuum furnaces, glass production, military and space applications where oxygen is not present.

Extreme high temperature stability & strength
Maintains strength at elevated temperatures
Low distortion at high temperature
Molybdenum must be used in vacuum or inert gas at high temperatures

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RAYCHIN LIMITED

Name: Molybdenum Fasteners
SKU: 0

Molybdenum Fasteners · Bolts / Nuts / Screws / Washers / Studs / Threaded Rods · Inch & Metric

Molybdenum Fasteners: Ultra-High Temperature Refractory Metal Bolts, Nuts, Screws, Washers, Studs & Threaded Rods

Pure Mo (≥99.95%) | TZM (Mo-Ti-Zr-C) | MoLa (Mo-La₂O₃) | ASTM B386 / B387

RAYCHIN LIMITED is a leading manufacturer of Molybdenum Fasteners – precision-engineered components produced from pure molybdenum and its alloys, delivering exceptional high-temperature strength, thermal stability, and resistance to creep in extreme environments. With a melting point exceeding 2600°C (4700°F), molybdenum fasteners retain structural integrity under vacuum, reducing atmospheres, and severe thermal cycling. Our comprehensive product line includes molybdenum bolts, molybdenum nuts, molybdenum screws, molybdenum washers, molybdenum stud bolts, and molybdenum threaded rods – all manufactured to the highest precision standards. Available grades include Pure Molybdenum (≥99.95%), TZM alloy (Mo-0.5Ti-0.08Zr-0.02C), and Molybdenum Lanthanum (MoLa) with enhanced recrystallization temperature. Our portfolio includes all standard and custom configurations manufactured to NAS, AN, MS, ANSI, ASTM, ASME, SAE, API, NACE, ISO, DIN and KS standards, including ASTM B386/B387, ISO 4017, ISO 4032, DIN 931, DIN 934, and ASME B18.2.1/18.2.2. Whether you require molybdenum fasteners for high-temperature vacuum furnaces, semiconductor sputtering equipment, sapphire crystal growth systems, glass melting electrodes, or aerospace propulsion components, RAYCHIN delivers precision, quality, and full traceability. All mechanical properties are presented in MPa and ksi (kilopound per square inch).

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Molybdenum Fasteners – Complete Product Range

Molybdenum Bolts

Molybdenum bolts include hex head bolts, heavy hex bolts, and hex head cap screws in inch and metric series. Manufactured to ASME B18.2.1 (inch), ISO 4014 / DIN 931 (metric), and ISO 4017 / DIN 933 (fully threaded). Available with full or partial thread, precision rolled threads for superior fatigue life. Ideal for high-temperature furnace assemblies, heat shields, and secure connections in ultra-high-vacuum systems.

Molybdenum Nuts

Molybdenum nuts are manufactured in hex, heavy hex, jam, and slotted configurations per ASME B18.2.2 (inch), ISO 4032 / DIN 934 (metric). Precision tapped with class 2B/6H threads. Used in conjunction with molybdenum bolts or studs to create secure, high-temperature-resistant connections in sputtering equipment, crystal growth furnaces, and nuclear applications.

Molybdenum Screws

Molybdenum screws available in socket head cap screws (ISO 4762/DIN 912), pan head (ISO 1580/DIN 85), flat head countersunk (ISO 10642/DIN 7991), and set screws (ISO 4026-4029/DIN 913-916). Precision machined with rolled threads. Designed for critical fastening in high-stress, high-temperature environments such as semiconductor chambers and heating element fixtures.

Molybdenum Washers

Molybdenum washers include flat washers (ASME B18.22.1, ISO 7089, DIN 125), spring washers (DIN 127), and lock washers (ASME B18.21.1). Precision stamped or machined from pure Mo or TZM alloy. Provide load distribution, prevent galling, and maintain clamping force under extreme thermal cycling. Essential for vacuum furnaces and high-temperature processing equipment.

Molybdenum Stud Bolts

Molybdenum stud bolts feature threads on both ends (double-end studs) for flange connections in high-temperature piping, pressure vessels, and furnace access doors. Manufactured to ASME B18.31.2 (inch) and ISO 898-1 (metric). Available in fully threaded or center-shank configurations. Withstand aggressive thermal environments in refineries, power generation, and chemical processing.

Molybdenum Threaded Rods

Molybdenum threaded rods provide continuous threads along the entire length, allowing custom-length fastening solutions. Available in lengths up to 3000mm (120") with UNC, UNF, and metric threads. Ideal for tie rods, anchors, and custom fabricated assemblies in vacuum furnaces, thermal evaporation systems, and semiconductor manufacturing equipment. Can be cut to length and combined with molybdenum nuts/washers.

Alloy Grades: TZM & MoLa

TZM alloy fasteners (Mo-0.5Ti-0.08Zr-0.02C) offer higher recrystallization temperature, improved strength, and creep resistance compared to pure Mo. MoLa alloy fasteners (Mo doped with La₂O₃) exhibit enhanced ductility and high-temperature stability. Both alloys available across all fastener types for applications exceeding 1400°C in vacuum or reducing atmospheres.

Aerospace & Military Standards

Our molybdenum fasteners meet applicable sections of NAS1351/1352 (socket head), NAS1802 (hex head), NASM 20426, MS16995, and AN42-AN73. Full compliance with ASTM B386 (plate/sheet/foil) and ASTM B387 (rod/bar/wire) for material and mechanical properties. Silver plating per AMS 2410 available for anti-galling. Cleanroom packaging available for semiconductor and aerospace applications.

Custom & Non-Standard Fasteners

Need special head configurations, proprietary drives (Torx, Robertson), non‑standard lengths, or unique thread forms? RAYCHIN engineers design and produce custom molybdenum fasteners to your exact specifications – any grade (pure Mo, TZM, MoLa), any condition (stress relieved, recrystallized), with full material traceability. Prototype to production volumes supported. In-house metallurgical laboratory ensures optimal performance.

Critical Applications of Molybdenum Fasteners

High-Temperature Vacuum Furnaces

Molybdenum fasteners are essential in vacuum furnace construction, including hot zones, heating element supports, heat shields, and hearth assemblies. They maintain structural integrity at temperatures exceeding 1700°C (3090°F) in vacuum or inert gas environments where tungsten is too expensive and superalloys fail. Used in sintering furnaces, brazing furnaces, and annealing furnaces.

Semiconductor & Sputtering Equipment

Molybdenum fasteners in semiconductor manufacturing equipment, including sputtering targets, PVD chambers, ion implanters, and wafer processing systems. Molybdenum's low coefficient of thermal expansion, high thermal conductivity, and non-contaminating properties (no outgassing) make it ideal for ultra-high-vacuum (UHV) environments. Essential for securing electrodes, shields, and process kits.

Sapphire Crystal Growth & Glass Melting

Molybdenum fasteners used in sapphire crystal growth furnaces (Kyropoulos, Czochralski) and glass melting electrodes. Molybdenum withstands molten glass corrosion and extreme temperatures required for LED sapphire substrate production. Fasteners secure crucible assemblies, heat shields, and electrode holders in aggressive molten environments.

Aerospace & Defense

Molybdenum fasteners in rocket engine components, nozzle assemblies, re-entry vehicle heat shields, and supersonic aircraft skin elements. Molybdenum alloys maintain strength at extreme temperatures where other metals would soften or melt. Used in thrust vector control systems and high-temperature structural joints.

Nuclear Engineering

Molybdenum fasteners in nuclear reactors, particle accelerators, and experimental fusion devices. Molybdenum exhibits excellent resistance to radiation damage and retains mechanical properties under neutron irradiation. Used for fuel cladding supports, control rod mechanisms, and plasma-facing component fasteners.

Medical & X-ray Equipment

Molybdenum fasteners in X-ray tube assemblies, radiation shielding components, and medical isotope production equipment. Molybdenum's high atomic number and thermal properties make it suitable for X-ray targets and collimators. Fasteners secure targets and cathodes under high-voltage, high-temperature operation.

International Standards & Global Designations – Molybdenum Fasteners

RAYCHIN LIMITED manufactures molybdenum fasteners from vacuum arc melted (VAR) or powder metallurgy (PM) material conforming to the most widely used national and international specifications. All material is traceable to the mill.

Designation	Standard / Specification	Description
Pure Molybdenum	Mo ≥99.9% – ≥99.95%	Unalloyed molybdenum, highest purity available; excellent thermal conductivity, low vapor pressure
ASTM B386 / B386M	Standard Specification for Molybdenum and Molybdenum Alloy Plate, Sheet, Strip, and Foil	Covers grades 360 (vacuum arc melted pure Mo), 361 (powder metallurgy pure Mo), 363 (TZM), 364 (powder metallurgy TZM), 365 (low C Mo), 366 (Mo-30W)
ASTM B387 / B387M	Standard Specification for Molybdenum and Molybdenum Alloy Bar, Rod, and Wire	Primary material specification for molybdenum fastener stock; covers same grades as B386
TZM Alloy	Mo-0.5Ti-0.08Zr-0.02C	Molybdenum alloy with titanium, zirconium, carbon for enhanced strength and recrystallization temperature
MoLa (Mo-La₂O₃)	Mo with 0.3-0.6% Lanthanum Oxide	Dispersion-strengthened molybdenum with improved ductility and high-temperature stability
ISO 4017 / DIN 933	Hex head cap screws – metric series	Dimensional standard for fully threaded hex bolts
ISO 4032 / DIN 934	Hex nuts – metric series	Dimensional standard for hex nuts
ASME B18.2.1 / B18.2.2	Square and hex bolts / hex nuts (inch series)	Dimensional standards for inch-series bolts and nuts
ISO 4762 / DIN 912	Socket head cap screws – metric	Dimensional standard for socket head screws
ISO 7089 / DIN 125	Flat washers – metric series	Dimensional standard for flat washers
AMS 7847 / AMS 7848	TZM bar and rod specifications	Aerospace material specifications for TZM alloy

ASTM B386 ASTM B387 Pure Mo 99.95% TZM MoLa ISO 4017 ISO 4032 DIN 931 DIN 934 ASME B18.2.1 ASME B18.2.2

Chemical Composition (Weight %) – Molybdenum Alloys for Fasteners

Our molybdenum fasteners are produced from vacuum arc melted (VAR) or powder metallurgy (PM) material conforming to ASTM B386/B387 and industry standards.

Pure Molybdenum (Grade 360 / 361) – Mo ≥99.95%

Element	Min %	Max %	Typical
Molybdenum (Mo)	99.9	Balance	99.95
Iron (Fe)	—	0.010	0.004
Nickel (Ni)	—	0.005	0.002
Silicon (Si)	—	0.010	0.0013
Carbon (C)	—	0.030	0.0028
Oxygen (O)	—	0.0070	0.005
Nitrogen (N)	—	0.002	0.002
Aluminum (Al)	—	0.002	0.0005
Calcium (Ca)	—	0.002	<0.001
Magnesium (Mg)	—	0.002	<0.0005

TZM Alloy (Grade 363 / 364) – Mo-0.5Ti-0.08Zr-0.02C

Element	Min %	Max %	Typical
Molybdenum (Mo)	Balance	Balance	~99.0
Titanium (Ti)	0.40	0.55	0.50
Zirconium (Zr)	0.06	0.12	0.08
Carbon (C)	0.01	0.04	0.02
Iron (Fe)	—	0.010	0.005
Nickel (Ni)	—	0.005	0.002
Silicon (Si)	—	0.010	0.005
Oxygen (O)	—	0.0030	0.002
Nitrogen (N)	—	0.002	0.001

MoLa Alloy (Mo with Lanthanum Oxide)

Element	Min %	Max %	Typical
Molybdenum (Mo)	Balance	Balance	~99.5
Lanthanum Oxide (La₂O₃)	0.3	0.6	0.4
Other impurities	—	0.10	<0.05

Metallurgical note: Molybdenum is a refractory metal with a body-centered cubic (BCC) crystal structure. Pure molybdenum fasteners are typically supplied in stress-relieved condition (recrystallization temperature ~1100°C). TZM alloy offers significantly higher recrystallization temperature (~1400°C) and improved creep strength through carbide dispersion strengthening. MoLa (lanthanated molybdenum) maintains ductility after high-temperature exposure due to oxide dispersion pinning grain boundaries. All molybdenum fasteners should be handled with care due to limited ductility at room temperature, becoming more ductile above ductile-to-brittle transition temperature (DBTT).

Complete Mechanical & Physical Properties – Molybdenum Fasteners (MPa / ksi)

Molybdenum fasteners are supplied in various conditions (stress relieved, recrystallized) per ASTM B387. Data represent typical values based on industry standards.

Mechanical Properties – Pure Molybdenum (Stress Relieved)

Condition	Tensile Strength (MPa)	Tensile Strength (ksi)	Yield Strength 0.2% (MPa)	Yield Strength 0.2% (ksi)	Elongation (%)	Hardness
Stress Relieved (typical)	620-760	90-110	550-620	80-90	10-20	250 HV (2500 MPa)
Recrystallized (annealed)	485-550	70-80	415-450	60-65	20-30	200 HV (2000 MPa)

Mechanical Properties – TZM Alloy

Condition	Tensile Strength (MPa)	Tensile Strength (ksi)	Yield Strength 0.2% (MPa)	Yield Strength 0.2% (ksi)	Elongation (%)	Hardness
Stress Relieved	860-1035	125-150	690-860	100-125	8-15	300 HV (3000 MPa)
Recrystallized	620-760	90-110	550-620	80-90	15-25	230 HV (2300 MPa)

Physical Properties – Molybdenum

Property	Metric	Imperial	Notes
Density	10.22 g/cm³	0.369 lb/in³	Pure Mo
Density (TZM)	10.16 g/cm³	0.367 lb/in³	Slightly lower due to alloying
Melting Point	2617°C	4743°F	Pure Mo
Boiling Point	4612°C	8334°F
Elastic Modulus (E)	324-329 GPa	47.0-47.7 x 10³ ksi	Stress relieved condition
Poisson's Ratio	0.293-0.31	0.293-0.31
Thermal Expansion (20-100°C)	5.1 x 10⁻⁶ /K	2.8 x 10⁻⁶ /°F	Very low CTE
Thermal Conductivity	138 W/m·K	960 BTU·in/(hr·ft²·°F)	Excellent conductivity
Electrical Resistivity	5.7 µΩ·cm	2.24 µΩ·in	At 20°C
Specific Heat	251 J/kg·K	0.06 BTU/lb·°F	At 25°C

High‑Temperature Performance of Molybdenum Fasteners

Molybdenum and its alloys are renowned for exceptional high-temperature strength and stability. Pure molybdenum maintains useful mechanical properties up to 1700°C (3090°F) in vacuum or reducing atmospheres, with TZM extending capability further through carbide strengthening. However, molybdenum oxidizes rapidly above 400°C in air, limiting use to vacuum, inert gas, or reducing environments unless protected by coatings.

Elevated Temperature Capabilities

Property	Pure Molybdenum	TZM Alloy	MoLa Alloy
Max Service Temp (vacuum/inert)	1700°C (3090°F)	1400-1500°C (2550-2730°F)	1700°C (3090°F)
Recrystallization Temp	1100°C (2010°F)	1400°C (2550°F)	1300-1500°C
Creep Resistance	Good	Excellent	Very Good
Tensile Strength @ 1000°C	~300 MPa (43 ksi)	~450 MPa (65 ksi)	~350 MPa (51 ksi)
Oxidation Onset in Air	400°C (750°F) – rapid formation of volatile MoO₃

High-Temperature Comparison – Refractory Metals

Alloy	Max Service Temp (Vacuum)	Density (g/cm³)	Typical Application
Molybdenum (Pure)	1700°C	10.22	Furnace hot zones, electrodes
TZM Alloy	1500°C	10.16	High-strength furnace components, rocket nozzles
MoLa (La₂O₃)	1700°C	10.20	Heating elements, wire applications
Tungsten (W)	2500°C	19.3	Highest temperature, but 2x density
Stainless Steel 316	~900°C	8.0	Lower temperature limit

Note: All molybdenum fasteners must be used in vacuum, inert gas, or reducing atmosphere (H₂) above 400°C to prevent catastrophic oxidation. For air applications, protective coatings (MoSi₂, etc.) may be applied.

Corrosion Resistance of Molybdenum Fasteners

Molybdenum exhibits excellent resistance to many corrosive media, particularly in reducing environments and in the absence of oxidizing agents. However, rapid oxidation occurs in air above 400°C.

Acid Resistance: Excellent resistance to hydrochloric acid (HCl), sulfuric acid (H₂SO₄) at moderate temperatures, and phosphoric acid (H₃PO₄). Resists most non-oxidizing mineral acids. Rapid attack in nitric acid (HNO₃) and other oxidizing acids.
Alkalis: Generally good resistance, but can be attacked by fused alkalis. Resistant to many molten salts.
Liquid Metals: Excellent resistance to liquid lithium, sodium, potassium, and bismuth, making it valuable in nuclear coolant systems.
Halogens: Resistant to fluorine, chlorine, and bromine at moderate temperatures; attacks at higher temperatures.
Oxidation: Forms volatile MoO₃ above 400°C in air; requires protective atmosphere or coating for high-temperature air service.
Hydrogen: Excellent resistance to hydrogen attack even at high temperatures (unlike steel).
Sulfur Compounds: Good resistance to sulfur, hydrogen sulfide, and sulfur dioxide.
Glass Corrosion: Outstanding resistance to molten glass, widely used in glass melting electrodes and stirrers.
Bimetallic Corrosion: Can be safely connected to tungsten, tantalum, and graphite. Avoid direct contact with aluminum, zinc, and copper at high temperatures due to eutectic formation.

Manufacturing Standards – Molybdenum Fasteners

All molybdenum fasteners are manufactured and tested to meet the following standards:

ASTM B386ASTM B387AMS 7847ASME B18.2.1ASME B18.2.2ISO 4017ISO 4032DIN 931DIN 934ISO 4762DIN 912ISO 7089DIN 125NAS1351EN 10204 3.1/3.2

We offer surface finishes: black (as-machined), chemical cleaned, ground, polished, and passivated. Special coatings (MoSi₂, Al₂O₃, Y₂O₃) available for oxidation protection. Full traceability and destructive/non‑destructive testing available (UT, PMI, MPI). ISO 13485 certified for medical applications with cleanroom packaging available.

Why RAYCHIN LIMITED – The Molybdenum Fastener Authority

Refractory metal expertise: Decades of experience with molybdenum, TZM, and MoLa alloys. We ensure precise processing: stress relieving, recrystallization annealing, and surface finishing per ASTM B386/B387 standards. In‑house PMI verifies chemistry of every heat. Our molybdenum fasteners achieve full traceability and certified properties.

Global certifications: ISO 9001, AS9100D, ISO 13485 (medical), PED, API Q1, NADCAP accredited processes. All fasteners supplied with EN 10204 3.1/3.2 certifications, material test reports, and NACE compliance when required.

Precision machining & thread rolling: CNC turning and precision thread rolling ensure accurate head geometry and thread form per ASME, ISO, and DIN standards. Class 2A/3A/6g thread fit. 100% inspection available. Special tooling for molybdenum's unique machining characteristics (brittle behavior at room temperature).

Custom solutions: Special head configurations, proprietary drives, non‑standard lengths, custom alloys, and tailored packaging. In-house metallurgical laboratory and failure analysis capabilities. Prototype to production volumes supported. Cleanroom wash and packaging available for semiconductor and medical applications.

Contact the molybdenum fastener experts

Request a quotation for molybdenum bolts, nuts, screws, washers, stud bolts, threaded rods – any grade (Pure Mo, TZM, MoLa) – any standard (ASME, ISO, DIN, NAS) – any condition (stress relieved, recrystallized), any quantity. Global delivery. Mechanical data in MPa/ksi available for all products.

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