When nickel, titanium or zirconium alloys are not enough...

Tantalum flat head screws are best known for its unmatched corrosion resistance and chemical inertness. Tantalum screws have a similar corrosion resistance to that of glass, but all of the typical mechanical and electrical properties of a metal.

Tantalum flat head screws are also extremely stable at high temperatures, since tantalum has a melting point around 3000°C. High temperature applications require vaccum or inert gas since tantalum may embrittle when used in oxygen rich environments above 250°C.  Tantalum screws are also one of the most bio-compatible metals available and is also radio-opaque due to its high density (16.68 g/cm3).

All tantalum flat head screws are available in commercially pure tantalum and tantalum 2.5% tungsten (Ta-2.5%W).

Contact us to see if your required tantalum flat head screws are in stock and how our engineers may help you with your tantalum fastener application.

ResourcesTantalum Torque Spec

Screw TypesButton Head Cap ScrewsFlat Head ScrewsHex Cap ScrewsPan Head ScrewsSet ScrewsSocket Head Cap Screws 


Tantalum Flat Head Screw Features and Benefits

Tantalum flat head screws are characterized by having a head with a top flat surface (which can feature either a slotted, phillips or allen driver) and bottom that is cone shaped or countersunk. With this design, the head of the screw can align flush or below the surrounding surface having obvious benefits.

Tantalum Slotted vs. Phillips Driver 

 Slotted Head Advantages Phillips Head Advantages 
  • Slotted head screws tend to strip less than Philips, especially in harsh environments
  • Slotted heads are typically better in applications where it's going to be unscrewed and re-done periodically, as the head tends to wear less.

  • In dirty environments, a flat head is much easier to clean out

  • Phillips head offers a much stronger joint since it can tolerate more torque.

Countersink Angle

For most flat head screw designs the angle of countersink is usually 82° for UNC and UNF applications however other angles ranging from 60° -120° could be specified. 

Thread Type Normal Flat Head Countersink Angle

UNC / UNF

82°

Aerospace 100°
ISO Metric / Imperial 90°

 


 Tantalum Grades, Specifications and Chemistry

Tantalum (Commercially Pure)

Commercially pure tantalum metal is 99.95% pure tantalum has some o the best corrosion resistant properties of any metal. While its corrosion resistance is exceptional, it is relatively soft and mechanically similar in strength to copper.

Tantalum Specifications: UNS R05200, ASTM B521, B708

Tantalum Chemistry

 

Tantalum 2.5% Tungsten (Ta-2.5W)

This grade of tantalum alloyed with 2.5% tungsten provided better overall strength while maintaining its exception corrosion resistant properties. For tantalum fastener applications this is usually preferred.

Tantalum 2.5% Tungsten Specifications: UNS R05252, ASTM B521, B708

Tantalum 2 5 Tungsten Chemistry

 


Physical Properties

  • Density 16.6 g/cc
  • Melting Point 3290 K, 2996°C, 5462°F
  • Boiling Point 5731 K, 6100°C, 9856°F
  • Coefficient of Thermal Expansion (20°C) 6.5 x 10(-6) / °C
  • Electrical Resistivity (20°C) 13.5 microhms-cm
  • Electrical Conductivity 13% IACS
  • Specific Heat .036 cal/g/°C
  • Thermal Conductivity .13 cal/cm(2)/cm°C/sec

Tantalum Tensile Data

Tensile Data


 

Tantalum Iso-Corrosion Curves

Specialty Metal H2SO4 Iso-Corrosion Curve

Specialty Metal HCl Iso-Corrosion Curve


Tantalum Corrosion Resistance Table

TANTALUM SHOWS A NIL CORROSION RATE TO THE FOLLOWING MEDIA

For all temperatures up to at least 302F (150C) unless otherwise indicated 

Acetic acid
Acetic anhydride
Acetone
Air,<300°C (570°F)
Alcohols
Aldehydes
Aluminum chloride
Aluminum nitrate
Aluminum sulfate
Amines
Ammonium bicarbonate
Ammonium carbonate
Ammonium chloride
Ammonium nitrate
Ammonium acid phosphate
Ammonium phosphate
Ammonium sulfate
Amyl acetate or chloride
Aniline hydrochloride
Aqua regia
Barium carbonate
Barium chloride
Barium hydroxide
Barium nitrate
Benzoic acid
Body fluids
Boric acid
Bromine, dry, <300°C (570°F)
Bromine, wet
Butyric acid
Calcium bicarbonate 
Calcium bisulfates
Calcium bisulfites
Calcium carbonate
Calcium chloride
Calcium hydroxide
Calcium hypochlorite
Carbolic acid
Carbon dioxide
Chloric acid
Chlorinated brine

Chlorine, dry, <250°C (480°F)
Chlorine, wet, <350°C (662°F)
Chlorine oxides
Chloroacetic acid
Chromic acid
Chrome plating solutions
Citric acid
Cleaning solutions
Copper salts
Dichloroacetic acid
Dimethylformaldehyde
Ethylene dibromideEthyl sulfate
Fatty acids
Ferric chloride
Ferric sulfate
Ferrous sulfate
Food stuffs
Formaldehyde
Formic acid
Fruits
Glycerine
Graphite, <1000°C
Hydroiodic acid
Hydrobromic acid
Hydrocarbons
Hydrochloric acid
Hydrogen bromide, <400°C
Hydrogen chloride, <350°C
Hydrogen iodide
Hydrogen peroxide
Hydrogen sulfide
Hydroxyacetic acid
Hypochlorus acid
Iodine, <300°C (570°F)
Ketones
Lactic acid
Lead salts
Magnesium chloride
Magnesium hydroxide
Magnesium sulfate

Maleic acid
Manganous chloride
Methyl alcohol
Methylsulfuric acid
Milk
Mineral oils
Mixed acids (sulfuric-nitric)
Motor fuels
Nickel salts
Nitric acid
Nitric acid, fuming
Nitric oxides
Nitrogen, <300°C (570°F)
Nitrous acid
Nitrosyl chloride
Organic chlorides
Organic acids
Organic esters
Organic salts
Oxalic acid
Oxygen, <300°C (570°F)
Pechloric acid
Petroleum products
Phenol
Phosphoric acid, <4ppmF,<180°C
Phosphorus, <700°C (1290°F)
Phosphorus chlorides
Phosphorus oxychloride
Phthalic anhydride
Pickling acids, except HNO3-HF
Potassium bromide
Potassium chloride
Potassium dichromate
Potassium ferricyanide
Potassium iodine-iodine
Potassium nitrate
Potassium permanganate

Potassium sulfate
Potassium thiosulfate
Propionic acid
Refrigerants
Sea water
Silver nitrate
Sodium acetate
Sodium aluminate
Sodium bisulfate, solution
Sodium bromide
Sodium chlorate
Sodium chloride
Sodium citrate
Sodium cyanide
Sodium dichromate
Sodium hypochlorite
Sodium nitrate
Sodium nitrite
Sodium phosphate
Sodium silicate
Sodium sulfate
Sodium sulfide
Sodium sulfite
Sodium thiosulfate
Stearic acid
Succinic acid
Sugar
Sulfamic acid
Sulfur, <500°C (930°F)
Sulfur chlorides
Sulfur dioxide
Sulfuric acid, to 175°C (350°F)
Sulfurous acid
Sulfuryl chloride
Tannic acid
Tartaric acid
Thoinyl chloride
Tin salts
Zinc chloride
Zinc sulphate

TANTALUM SHOWS LIMITED CORROSION RESISTANCE TO THE FOLLOWING MEDIA

Air,>300°C (570°F)
Ammonia
Ammonium hydroxide
Fluoride salt
Hydrofluoric acid

Hydrogen, >300°C (570°F)Hydrogen fluoride
Oleum (fuming sulfuric acid)
Potassium carbonate
Potassium hydroxide, dilute

Potassium hydroxide, conc.
Potassium pyrosulfate, molten
Sodium bisulfate, molten
Sodium carbonate
Sodium hydroxide, dilute

Sodium hydroxide, conc.
Sodium pyrosulfate, molten
Sulfur trioxide
Sulfuric acid, >175°C (350°F)

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