Fast Facts About ASTM B994September 28, 2017
With the industry in search of better methods to protect fasteners from failure, ASTM B994 offers a novel solution to resisting corrosion in critical offshore bolting operations. The standard is designed to improve a manufacturer’s control of the production process and recommends new, more rigorous testing to improve worker safety and reduce the long-term costs of bolting. Suggesting a Nickel-Cobalt alloy as the new practice for fastener electroplating, ASTM B994 promises to revolutionize bolt theory and practice.
So what does your team need to know about ASTM B994, and why should your company invest in compliant fasteners? Here are five fast facts to get you started.
API Specification 20E is an integral part of the industry’s response to bolt failure. First introduced in 2012, API 20E is the standard that will define bolting for the 21st century.
Many of the ASTM tests recommended and described by ASTM B994 are also referenced and required by API 20E, including frequent hydrogen embrittlement testing in compliance with ASTM F519 specifications. In addition, API 20E specifically prohibits the use of Zinc electroplating, an action later echoed by BSEE in all offshore applications. The ASTM B994 plating process does not require studs to be undersized or nuts to be oversized, which is also not permitted by API 20E but is a requirement when using sacrificial coating systems such as Zinc and PTFE.
The production and testing methods described in ASTM B994 make sure that fastener companies and their customers come into compliance with API 20E, leading to a safer and more cost-effective solution to critical bolting operations.
Hydrogen embrittlement has been found at the center of catastrophic bolt failure in recent years, costing the industry billions of dollars. In many of these failures, the presence of sacrificial coatings such as Zinc and its alloys was found to be one of the contributing factors. Where sacrificial coatings generate hydrogen during their cathodic reaction, inducing it into their fasteners’ steel substrate, non-sacrificial Nickel-Cobalt does not produce hydrogen as it corrodes. At the same time, the toughness of Nickel-Cobalt and the controlled electroplating process described in ASTM B994 act as a barrier to environmental hydrogen found in offshore and subsea environments. With these factors and processes acting in fasteners’ favor, ASTM B994 Nickel-Cobalt plating greatly reduces the risk of hydrogen embrittlement.
ASTM B994 describes a new lab test that is designed to better simulate a fastener’s real world environment. This new evaluation allow a company to understand more about their fasteners’ performance in the field and to help customers predict when their bolting system is nearing failure. ASTM B994 calls this a galling test, also known as a Fastener End of Life Test (FELT).
In the galling test, fasteners are placed under tension and subjected to a salt fog environment to simulate their real world applications. Samples are then opened periodically to check their condition. If the fasteners still turn, the company knows that bolts in the field are still performing. To comply with the ASTM B994 Class 1 testing tier, a fastener company must perform this test every 120 days for a minimum of two years.
It is always better to replace a fastener before it fails than to test its mechanical limits. Getting to fasteners early lets companies bypass costly and dangerous procedures such as hot bolting, making the replacement process faster, cheaper, and easier for all involved. The galling test lets a fastener company know when it’s time to recommend a turnaround to their customers so they can act before their bolts seize.
Compliant with ASTM B994, the galling test is a true torture test designed to put safety first. We find it to be such an effective testing environment that we also apply its torquing parameters to the other tests described in ASTM B994. This helps us keep a record of performance for all lots in service and allows us to immediately alert customers once it is time to rotate out a batch of bolts.
ASTM B994 defines seven different testing processes to protect fasteners from corrosion. These tests are further defined by four class levels that tell a customer which tests were performed and how often a fastener company using ASTM B994 performs them. In addition to the tried-and-true industry standard salt fog/spray test, ASTM B994 also describes a chemical composition test, a hydrogen embrittlement test, an electrochemical corrosion rate test, a modified (cyclic) salt fog/spray test, an acid & salt fog CASS test, and a galling test (more on this one in a second).
In addition to these mechanical, chemical, and environmental testing methods, ASTM B994 also defines acceptance tests for appearance, adhesion, and coating thickness. These testing specifications make sure that ASTM B994 bolts control and evaluate every production variable.
In addition to these testing classes, ASTM B994 further outlines four service conditions that relate to coating thickness, measured in micrometers (μm). For a fastener to stand up to the corrosive environment present in critical bolting operations, yet maintain its mechanical properties and not require oversizing nuts or undersizing stud bars, the Nickel-Cobalt plating must have a thickness of 18μm, following SC18.
With rigorous testing and production standards, ASTM B994 fasteners outstrip every other coating system in performance and reliability. When ordering fasteners for offshore and subsea applications, ask the manufacturer if they comply with ASTM B994 SC18 Class 1.
ASTM B994 suggests that each production lot be individually marked so that information about your fasteners can be accessed at all times. One of the biggest issues contributing to bolt failure in the past has been a lack of information regarding which bolts are nearing the end of their life. With a manufacturer’s mark suggested by ASTM B994, safety and maintenance crews can quickly identify a fastener’s origin and request testing data from the fastener company. This also allows crews to report field failures quickly and to track down the rest of the production lot in service before further incident. When evaluating a company selling ASTM B994 bolts, ask if they have a traceable marking system.
Nickel-Cobalt alloy was first used by NASA to coat critical parts that needed to resist high temperature environments. Later on, the military began using it in corrosive offshore applications similar to marine and subsea facility conditions. Nickel-Cobalt alloy is incredibly tough, and unlike other leading coating systems such as Zinc and Zinc alloys is not sacrificial. It is highly resistant to corrosion due to its constituent metals’ unique properties, and will stand up to temperatures that other coating systems will not. The corrosion tests specified in ASTM B994 Class 1 make sure that every fastener plated in Nickel-Cobalt following ASTM B994 processes works as advertised, providing the most technically merited fastener in the industry. ASTM B994 fasteners do what other fasteners can’t.
Why ASTM B994?
The industry is on the cusp of an evolution in fastener technology. With new specifications defined to improve efficiency and increase safety, novel coating systems are poised to become the new standard in offshore and subsea critical bolting operations. Nickel-Cobalt alloy electroplating, produced and implemented following ASTM B994 SC18 Class 1, provides the most reliable fasteners in the industry. They are compliant with the highest level of industry standards, undergo the most rigorous testing procedures, maintain consistent coating thickness, and offer unparalleled protection from corrosion. By complying with these specifications, companies can be sure that ASTM B994 bolting systems are committed to the safety of their crews.
Are you ready to to revolutionize your bolting practices at your facility, increase worker safety, and comply with API 20E specifications? Contact us today to learn more and to let us how we can better serve your exploration team.