PTFE is short for Polytetrafluoroethylene, a chemical applied to common bolting materials (such as B7M stud bolts) to provide corrosion and chemical resistance.
Normally when we talk about the PTFE coated on the stud bolt and other fasteners,we always refer to Teflon® and Xylan®.
PTFE coated studs have been used for many years within the bolting industry, especially in any application that requires corrosion resistance or in offshore applications.
While PTFE coated stud bolts (including Xylan coated studs bolts) have corrosion-resistant properties.
PTFE coating ,also Teflon is a fluorocarbonsolid, as it is a highmolecular weightcompound consisting wholly ofcarbonandfluorine. PTFE ishydrophobic: neither water nor water-containing substances wet PTFE, as fluorocarbons demonstrate mitigatedLondon dispersion forcesdue to the highelectronegativityof fluorine. PTFE has one of the lowest coefficients offrictionof any solid.
PTFE is used as anon-stick coatingfor hardware It is nonreactive, partly because of the strength ofcarbon–fluorine bonds, and so it is often used in containers and pipework for reactive and corrosive chemicals
FCC PTFE coated stud bolt A193 B7M A194 2HM nuts
Surface:black,galvanized,HDG,blue. FluoroCarbon Coated
Whitford Quality Approved Coater Xylan 1070 Coated Stud Bolt, Xylan Coated stud Bolts, PTFE Fluorocarbon Coated A193 B7M Stud Bolt &A194 2HM NUTS
Fluorcarbon coating-Surface Coatings XYLAN 1070. XYLAN 1024.
Diameter:1/4″~3 3/4″
Length:20mm~6000mm(usually 12 feet)
Grade :B7
Standard: M6-M100
Material: ASTM A193 B7M
Surface finished: PTFE Xylan Coated.
Standard: ANSI B18.1.1.
Stud bolts, a term used for cut-to-length all thread rod, are used for: bolting together flanges, anchor bolting, as well as general fastening.
ASTM A193 Grade B7M Specification for high tensile bolts, screws, stud bolts, threaded rods, anchor bolts and other externally threaded fasteners, made from chromium-molybdenum alloy steel.
ASTM A193 Grade B7M is a standard material specification for chromium-molybdenum alloy steel fasteners for use in high tensile, high temperature and special purpose applications. Grade B7M is a heat-treated chromium-molybdenum alloy steel with minimum tensile requirement of 100 ksi, yield of 75 ksi and maximum hardness of 99 HRB. ASTM A193 specification covers requirements for chemical composition, mechanical properties, hardness, heat-treatment, recommended nuts-washrs for Grade B7M fasteners. The difference between B7 & B7M is the hardness testing requirement for each bolt from a given lot in the latter.
ASTM A193 Grade B7M Chemical Composition
| Element | Alloy Steel |
|---|---|
| Chromium Molybdenum SteelA | |
| CompositionB, % | |
| Carbon | 0.37 – 0.49C |
| Manganese | 0.65 – 1.10 |
| Phosphorus | 0.035 max |
| Sulfur | 0.040 max |
| Silicon | 0.15 – 0.35 |
| Chromium | 0.75 – 1.20 |
| Molybdenum | 0.15 – 0.25 |
ASTM A193 Grade B7M Mechanical Properties
| Diameter, inch. | Tensile Strength, min, ksi | Yield Strength, min, 0.2% offset, ksi | Elongation in 4D, min, % | Reduction of Area, min, % | Hardness, max |
|---|---|---|---|---|---|
| 4 and under | 100 | 80 | 18 | 50 | 235 HBW or 99 HRB |
| over 4 to 7, inclusive | 100 | 75 | 18 | 50 | 235 HBW or 99 HRB |
Note: To meet the tensile requirements, the Brinell hardness shall be over 200 HBW (93 HRB).
Heat Treatment: Quenched & Tempered at 1100º F minimum.
Recommended Nuts & Washers For A193 B7M stud bolt
| Nut Specification | Washer Specification |
|---|---|
| ASTM A194 Grade 2HM | ASTM F436 |
Xylan coating because of its reputation in the Oil and Gas Industry as one of the premium coating providers for bolts and nuts. As a Qualified Approved Coater, our PTFE coated bolts and nuts have been used in various countries in South America,southeast Asia.Middle east.
COATING/PLATING OPERATING TEMPERATURES
- Cadmium Electroplating
– High Service Temp: 608o F.
– Low Service Temp: N/A; solid below 607o F. - Zinc or Zinc-Nickel Electroplating
– High Service Temp: 788o F.
– Low Service Temp: N/A; solid below 788o F. - Hot Dip Galvanizing
– High Service Temp 800o F.
– Low Service Temp: N/A; solid below 800o - DuPont Teflon® 857G Series PTFE
– High Service Temp: 500o F.
– Low Service Temp: N/A - Xylan® 1400 Series PTFE
– High Service Temp: 450o F. continuous, 550o F. intermittent
– Low Service Temp: -320o F. - Xylar 2® Cermet
– High Service Temp: up to 1,000o F.
– Low Service Temp: N/A - Zinc Phosphate
– Ambient Temperature
What is the difference between stud bolt A193 Grade B7 & A193 Grade B7M?
Several ASTM specifications are followed by an “M” that denotes it being an equivalent metric standard. While there is actually an A193M Grade B7 specification which is applicable to metric fasteners, this is not the case with ASTM A193 Grade B7M. This is a different grade of material than A193 Grade B7. So how exactly does A193 Grade B7M differ from A193 Grade B7?
There are some significant differences in both the mechanical properties and the testing requirements of A193B7M and A193B7. For instance, A193B7M has a minimum tensile strength of 100 ksi for diameters under 4”. The minimum tensile strength for A193B7 is 125 ksi for diameters under 2-1/2”, and 115 ksi for 2-1/2” – 4” diameter. Hardness is probably the most significant difference between A193B7M & A193B7. The maximum hardness of ASTM A193B7M is 235 HB or 99 HRB, while the maximum hardness of A193B7 is 321 HB or 35 HRC. The most notable difference from a manufacturing perspective is that when providing A193B7M bolts, every individual bolt or stud in the lot must be hardness tested. A193B7M fasteners will also require a different grade of heavy hex nut than A193B7, which would be ASTM A194 Grade 2HM.
While A193B7 is specified relatively often in the construction industry, A193B7M is a specification that is not seen as regularly. This makes it important to understand the differences between the two specifications so that the correct material is ultimately provided.
How to order our PTFE coated ASTM A193 B7M Stud bolt with 2 A194 2HM hex nuts?
Example#
PTFE Coated Stud Bolt And Nut ASTM A193 Gr. B7M Stud bolt
Standard: ASME B18.31.2/ASME B18.2.2
Grade:ASTM A193 Gr. B7M Stud bolt with ASTM A194 Gr. 2HM HEAVY HEX NUTS
Inch Thread
Finish: PTFE COATED
Available Size: 1/4inch – 4inch