PROTINN: The New Standard in B7 Studs

PROTINN purple bolts for better torque loads

Meet the game-changing bolt that delivers 3-4 times better torque loads than other B7 studs.

A New Stud Standard

Get unmatched safety, torque load accuracy and performance from the new PROTINN bolt with Xylan 1424 purple coating. This isn’t just another bolt – it’s a groundbreaking upgrade that lets you worry less about downtime, costly equipment failures and missed deadlines.

Developed by experts at Houston Fastener with decades of oil and gas expertise, PROTINN’s innovative design creates reliable gasket seals for better flange assembly safety and durability. Confidently take on your toughest jobs using a stud that outperforms other bolts at every turn.

PROTINN purple bolts for better flange assembly

Best-in-Class Benefits

PROTINN stand apart from the competition with unrivaled features:

Precision

Consistent accuracy for a superior torque-tension relationship

Reliability

A dependable ±10% k-factor – an industry first

Durability

Superior corrosion resistance (7P/0.3% red rust rating)

Performance

Exact stud load with zero underloading concerns

Traceability

Single-source manufacturing and in-house testing

What’s Your K-Factor?

K-factor, also known as nut factor, is a value for calculating the target input torque for your fastener. K-factor testing is essential for PTFE bolts because there is no manufacturing standard in the industry for the coating applied to these fasteners.

Since K-factor is the only experimentally tested constant in the equation for torque, it’s the only nonstandard variable when calculating torque.

Traditional B7 studs widely used in the oil and gas industry demonstrate broad variations (up to 44%) in torque load. Over-tapping of the nut is the primary reason for such high inconsistencies in k-factor.

Most manufacturers over-tap when manufacturing PTFE-coated studs because the nut wouldn’t be able to run down the stud after the undercoating and the application of the PTFE coating. The result? Inconsistent flange assemblies that can lead to leaks and equipment failure.

PROTINN – The Solution for Properly Torqued Fasteners

PROTINN solves long-standing torque load variation challenges with an industry-best ±10% k-factor. This means you get consistent and repeatable bolt loads on your flange assemblies.

K-factor Box and Whiskers chart: Industry "blue" bolts vs. PROTINN

In addition to a great k-factor for bolt tensioning, PROTINN also provides superior corrosion resistance. When applied at 1 mil (25 micron) dry film thickness over zinc-phosphated steel panels, the coating has exceeded 1,500 hours of the ASTM B117 salt fog test. With the same pretreatment, 30 cycles DIN 50018 (2.0 liters SO2) using the Kesternich test are achieved – both with less than 15% red rust.