|Committee A05 on Metallic-Coated Iron and Steel Products
100 Years of Fighting Corrosion
(See the sidebar on How Metallic Coatings Protect Steel.)
In the United States, corrosion directly costs a total of $276 billion per year.1 In most years, this dwarfs the annual cost of weather-related disasters by perhaps an order of magnitude. Much of this corrosion involves steel and iron and the best way to protect these materials is with metallic coatings.
For 100 years, Committee A05 on Metallic-Coated Iron and Steel Products has been on the front lines of the battle against iron and steel corrosion. Simply put, the purpose of Committee A05 has been and continues to be devoted to reducing this damage to our infrastructure. This mission is embodied in the committee’s scope, which reads in part:
The promotion of knowledge, the stimulation of research, and the development of standards in the area of iron and steel products protected against corrosion by use of metallic coatings, and non-metallic coatings which may be specified for use as supplemental protection.
Committee A05 proudly celebrates its centennial in 2006. For the past century we have been devising specifications and test methods to improve the quality, usefulness and longevity of the products under our jurisdiction.
Today Committee A05 membership totals 218, including 99 producers, 48 users, and 72 general interest members.
The metallic-coated iron and steel products covered by Committee A05 standards include sheet, wire, tube and corrugated steel pipe, as well as structural and hardware components. These products represent a substantial portion of the output of the North American steel industry. For instance, in 2004, almost 19 million tons of coated sheets (produced on approximately 80 coating lines) were shipped from North American producers. These products are used in the construction and building industries, constitute a large portion of the body mass of all automobiles, vans and light trucks, and are used extensively in the manufacture of appliances of all sizes, as well as for cabinets of electrical and electronic equipment. These and many other end uses require coated iron and steel products of high quality, many of the aspects of which are covered by the widely used A05 specifications.
Early History of Committee A05
The corrosion of iron and steel products has always been of key interest to ASTM members. Early in the history of the Society, differences of opinion concerning the variability in corrosion rates of iron and steel not only caused heated debates, but even led to lawsuits. Lack of knowledge of the effect of various environments on corrosion was recognized as a major shortcoming.
To deal with this issue, the Society, at its 1906 meeting, formed “Committee U” (changed to Committee A05 in 1910) to investigate the corrosion of iron and steel. The early work of the committee was devoted to conducting field tests to develop comparative data for different materials under identical conditions of exposure. The first tests were designed to develop knowledge of the effect of compositional and manufacturing conditions such as segregation on the corrosion behaviour of the base iron and steel. Sample billets from selected ingots were drawn into rod and wire, galvanized, formed into fence fabric and exposed at sites around the old Carnegie Institute of Technology in Pittsburgh, Pa.
In addition to wire, committee activities evolved into exposure tests of sheet products, both bare and coated, at sites across the United States. Laboratory test methods were also developed to produce accelerated corrosion test procedures. The results of these exposure and laboratory tests have been reported in several ASTM Special Technical Publications and represent a considerable body of knowledge of the corrosion behavior of both bare and coated iron and steel products. Exposure test programs continue today.
With the improvement of manufacturing methods, such as the evolution of high-speed continuous galvanizing lines in the 1950s, the committee became more involved in the preparation of specifications for coated products. Also at that time, ASTM had a growing interest in the formation of a committee devoted exclusively to the corrosion of metals. With the founding of Committee G01 on Corrosion of Metals in 1964, Committee A05 developed a new direction that was more focused on products and less on exposure tests. Any exposure tests under way would be carried to completion, but no new exposure tests would be started. This shift was reflected in the changing of the name of the committee from “Corrosion of Iron and Steel” to “Metallic-Coated Iron and Steel Products.”
Committee A05 Standards
The oldest continuing A05 standard is A 90, Standard Test Method for Weight [Mass] of Coating on Iron and Steel Articles with Zinc or Zinc-Alloy Coatings, originally published in 1923. However, an earlier coating specification, A 53, Standard Specification for Pipe, Steel, Black and Hot-Dipped, Zinc Coated Welded and Seamless, exists, which was first published in 1915 by Committee A01 on Steel, Stainless Steel, and Related Alloys. The oldest continuing standard issued by each A05 subcommittee is listed in Table 1.
In 1990, A 902, Terminology Relating to Metallic-Coated Steel Products, was approved. With additions over the years, A 902 now contains over 50 terms. Each definition is dated, so the subcommittee can review and update them when needed. A number of abbreviations are also included. A general listing of keywords is included as an appendix to aid A05 subcommittees in selecting appropriate keywords for their standards.
Today there are 94 standards under the jurisdiction of Committee A05.
A05 Committee Structure
Committee A05 consists of 10 subcommittees that are focused on various major product categories and test methods, exposure test programs, terminology, and administrative activities.
Subcommittee A05.07 on Test Methods
The description of technical requirements necessitates the development of test methods to measure conformance with requirements. Subcommittee A05.07 is responsible for measurement standards, and this activity has been a challenging one with the advent of several new coatings. The subcommittee recently published a new standard practice, A 1030, on measuring flatness characteristics of steel sheets. This practice has been referenced by Committee A01 in its specifications for steel sheet products.
Giulio Scartozzi is the current chair of A05.07.
Subcommittee A05.11 on Metallic-Coated Sheets
The use of metallic-coated steel sheet is increasing with the growth in industrial metal buildings, steel framing members for both commercial and residential structures, and the extended corrosion warranties of automobiles. The graph in Figure 1 shows this growth over the last decade.
For many years the most common metal coatings were zinc and zinc-iron alloy (also referred to as galvanize and galvanneal, respectively). Other coatings became available for specialized applications such as lead-tin (terne) coatings used for fuel tanks and electrical applications, and aluminum coatings used for heat-related applications such as toasters.
Some coatings have been developed that offer improved corrosion-resistance and other features, such as aluminum coatings, 55% aluminum-zinc alloy coating, and zinc-5% aluminum alloy coatings. These products offer enhanced corrosion resistance in atmospheric exposure and other applications. Recent committee activity has included discussion, balloting, and approval of a new zinc-aluminum-magnesium coated sheet specification, A 1046/A 1046M, Specification for Steel Sheet, Zinc-Aluminum-Magnesium Alloy-Coated by the Hot-Dip Process.
The most widely used method of applying metallic coatings to steel sheet is the hot-dip process. In fact, the coatings mentioned above are all applied by the hot-dip process. In addition, technologies have been developed to apply both thin and thicker coatings electrolytically, and two relatively new specifications have been approved for zinc and zinc-nickel alloy coatings applied by the electrolytic process.
The characteristics of a metallic-coated sheet product include corrosion resistance coupled with base metal properties. In the last two decades, steel manufacturing technologies have significantly affected base metal characteristics due to the increasing demand for more formable and/or higher strength steels. Consequently, Subcommittee A05.11 revised its specifications in 1994 to specify sheets using a broad range of properties. These revisions necessitated the elimination of traditional terms such as commercial quality, lock forming quality, and others with qualitative-subjective definitions in favor of terms associated with specific technical requirements. This change provides users with the opportunity to select specific steels based on the engineering requirements of their applications, as shown in Table 2.
This is the classification system now being used in A05 sheet specifications for describing the base steel sheet and which easily allows the addition of new grades and classes as they are developed.
Over the last 40 years, the appearance, corrosion resistance, and service life of metallic-coated sheets has been substantially improved by the development of superior paint coatings. Paints can be applied either before fabrication, as in the case of coil coated (prepainted) sheet for building cladding, or after fabrication, as in the example of painted automotive bodies.
For a metal roof fully exposed to the atmosphere, the improvement in product life made possible by using prepainted galvanized sheet is substantial. For instance, in a moderately corrosive environment, a G90 galvanized coating might last 15 to 20 years or more (see Figure 2) before red rust becomes evident. This red rust occurs in areas where the coating has been completely consumed by corrosion. If a high-quality, coil-coated prepaint system is applied prior to forming the roof panels, the time before initial signs of red rust might extend to 25 years or more. Furthermore, if the roof is repainted or repair painted when the initial signs of steel corrosion become visible, it may be another 10 to 15 years before corrosion is again evident. Some prepainted metal roof sheets are coated with thick-film organic coatings and are guaranteed against rust for up to 50 years. Subcommittee A05.11’s Specification A 755/A 755M, Specification for Steel Sheet, Metallic Coated by the Hot-Dip Process and Prepainted by the Coil-Coating Process for Exterior Exposed Building Products, covers the attributes of prepainted hot-dip metallic-coated steel sheet for exterior exposed building products.
The metallic coating on automotive body panels is relatively thin compared to those used on steel sheet for non-automotive outdoor applications, yet the synergy produced by the metallic coating, pre-treatments, and paint creates a system that is more than the sum of its parts, enabling modern auto body panels to resist corrosion for many years.
Marcia A. Demerest is the current chair of A05.11.
Subcommittee A05.12 on Metallic-Coated Wire
Metallic-coated wire and wire products are used for many applications that are very familiar to all of us and include such items as chain link fences, coat hangers, nails, staples, cages, bicycle wheel spokes, and barbed wire. Industrial uses include wire rope and strand, springs, telephone and telegraph line wire, highway guardrail strand, suspension bridges, gabions, and poultry fence fabric. Gabions, which are being used more and more along highways in the construction of rock walls, are among the newest products, and are described in A05 specifications A 974 and A 975.
These products are also manufactured with a wide variety of coatings such as zinc, aluminum, and copper, and sometimes in combination with poly vinyl chloride coating.
Donald L. Deetscreek is the current chair of A05.12.
Subcommittee A05.13 on Structural Shapes and Hardware
Many products need to be coated after fabrication because it is required that there be a zinc coating on all surfaces, or the substrate thickness is beyond the capability of other coating processes, or they are in complex shapes. In these cases the coating is applied by a batch process where each piece is coated individually.
The process involves cleaning the steel articles, applying flux to the surfaces, and immersing them in a molten bath of zinc for varying time periods to develop a thick, alloyed zinc coating. A typical hot dip coating produced in a batch process consists of a series of zinc-iron intermetallic alloy layers. Starting from the base steel, each layer contains a higher proportion of zinc until an outer layer of relatively pure zinc is reached.
The breadth of products coated by the batch process is very wide and includes such items as structural shapes, tanks, pails, pipe, fencing and highway guard rail. Currently, over 3 million tons of these and other batch galvanized articles are produced annually in North America. The standards of Subcommittee A05.13 specify the amount of coating and also help safeguard against any harmful consequences of batch coating, such as hydrogen embrittlement. Products coated by the batch process generally have the thickest zinc-based coatings covered by ASTM standards (up to 2.3 oz/ft2 minimum). Because of this, the service life of batch zinc-coated articles can be extremely long, as shown in Figure 2.2
Thomas J. Langill is the current chair of A05.13.
Subcommittee A05.15 on Wire Tests
Exposure tests are still an important activity, even though the responsibility for these tests has begun to diminish in Committee A05. Test studies on coated wire currently under way will be followed to completion. No new exposure tests of wire will begin without concurrence from Committee G01.
Thomas C. Britton, Jr. is the current chair of A05.15.
Subcommittee A05.17 on Corrugated Steel Products
A significant use of metallic-coated steel products is for corrugated steel pipe and structural plate for sewers and under-drains. These products are not as visible as others because they are typically buried underground. They are, however, important to all of us by providing safe conditions along our highways.
Jurisdiction over standards for these types of products was originally held by Subcommittee A05.11, but the scope of the specifications became significant enough to merit the attention of this dedicated subcommittee, which was formed in the late 1970s.
The metallic coatings used for corrugated pipe products include zinc, aluminum, 55% aluminum-zinc alloy and zinc-5% aluminum alloy, all of which may be supplemented by a polymer or bituminous coating.
In addition to describing the technical requirements of the corrugated products, practices have been developed related to the installation and design of sewer and under-drain applications. Also, a practice for life-cycle cost analysis has been developed.
J. Phil Perry is the current chair of A05.17.
Subcommittee A05.18 on Editorial and Terminology
Subcommittee A05.18 was organized in 1982 to provide editorial assistance in developing draft revisions for ballot. Previously, numerous “editorial” revisions were needed after a document was balloted, so the voter was never really sure that the document finally adopted was the same as was voted on, or if some unintended change took place in making editorial revisions. Using the subcommittee in this way decreases the number of corrections needed after balloting. The subcommittee is also responsible for preparing and managing A05’s terminology standard, A902.
Richard Nester is the current chair of A05.18.
Subcommittee A05.90, Executive
The members of this subcommittee are the elected officers of Committee A05, although all members of A05 are welcome to attend the meetings, which are normally held just prior to the semi-annual technical committee meetings. The business of the subcommittee is to oversee the functioning of the entire committee and to provide guidance and assistance.
Gary W. Dallin is the current chair of A05.90.
Subcommittee A05.91 on Awards
The purpose of this subcommittee is to identify A05 members who have shown exemplary service and are deserving of A05 and ASTM awards.
Brian C. Roberts is the current chair of A05.91.
Subcommittee A05.92 on Long Range Planning
A05.92’s purpose is to plan for and provide a forum to address the future needs or concerns of A05 activities, including but not limited to: consideration of individual participation, industry growth or viability, obsolete or new technologies, and educational, technical or industrial societies or organizations.
Richard F. Lynch is the current chair of A05.92.
A05 has been extremely fortunate to benefit from strong leadership over the years. This leadership has come in the form of main committee officers, members-at-large, subcommittee officers and those who have been the leaders and technical experts within subcommittees and task groups. Unfortunately, it is difficult to identify and recognize all those who have contributed. Nevertheless, those individuals who have held certain offices can be recognized.
Since the inception of the committee, 20 chairs have had the honor of leading this continually changing group of corrosion, coating, and steel experts. A05 chair, vice chair and secretaries are listed in Table 3.
Recognition for exemplary service to A05 and ASTM International is accomplished through peer awards given for outstanding contributions. Committee A05 has established two awards to recognize contributions by our members in addition to Society awards.
• The Committee A05 Outstanding Service Award recognizes outstanding and sustained service to Committee A05.
• The Kenneth J. Boedecker, Jr., Distinguished Service Award is the highest Committee A05 award, recognizing exceptional service to the committee, one of its subcommittees, or one of its activities.
• The Award of Merit and accompanying title of fellow is ASTM’s highest honor. A05 has been fortunate to have a significant number of its own qualify for this award over the years. From 1958 to 2004, 22 of its members have had their contributions recognized by being given the prestigious ASTM Award of Merit. Some A05 members were nominated for the award by other committees and as such are not listed.
All A05 award recipients are listed in Table 4.
Committee A05’s Future
After 100 years of operation, Committee A05 continues to be active and innovative in the management and creation of material and testing standards that govern the many millions of tons of coated steel produced annually, and which are used extensively in every facet of our daily lives. The committee actively promotes knowledge and research into these products and is continuously searching for ways to improve and add to its specifications. Member participation in committee activities remains at a high level. Committee A05 members represent a significant percentage of the metallic-coated steel production plants in North America, with a greater number of members representing users and general members.
If past history is a guide, Committee A05 will continue to find ways to expand into new areas and carry out its standardization mandate in its second century. This effort could result in further changes to maximize available resources and manage responsibilities in a cost effective manner. Certainly, the move ASTM International has championed toward electronic information transfer and on-line standardization activities will be a part of this different future and has already demonstrated the ability to draw more members into A05 activities. This greater global reach will also be reflected in increased international participation. In addition to their wide use on this continent, A05 specifications are already being used by a growing world-wide body of coated steel producers and users. The key to expanding their use will be to discover the best ways for committed people to work together effectively toward our common standardization objectives.//
1 “Corrosion Costs and Prevention Strategies in the United States”, NACE, 2001
2 American Galvanizers Association, www.galvanizeit.org