KnowledgeBase » Design

ILZRO Classifications of Sandelin Steels

Research carried out by the University of Cardiff in Wales for ILZRO (International Lead Zinc Research Organization) project took an in-depth look at the problem of silicon reactivity and included phosphorous as a reactive element also. The researchers varied the weight percentage of silicon and phosphorous and then assessed the reactivity of the steel at different galvanizing temperatures. This work led to a table of reactivity clas...
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Overlapped Surfaces

It is important to properly vent overlapping and contacting surfaces to prevent trapped moisture (from pickling or flux solution used in the galvanizing process) or gas from flashing to stream, which may result in localized uncoated surfaces. Additionally, pressure increases resulting from trapped moisture flashing to steam could possibly rupture the fabricat...
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Who Is Responsible for Avoiding Embrittlement?

ASTM A143/A143M spells out who is responsible for avoiding embrittlement. The responsibility lies on the designer, fabricator, and the galvanizer, but each party has different responsibilities. Choosing steel appropriate for the practices normally encountered in the galvanizing process and designing the product to avoid embrittlement are the res...
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Is hot-dip galvanized steel considered anti-sparking?

Yes, hot-dip galvanized coatings are anti-sparking and non-incendiary as are most zinc coatings. The exception is zinc coating alloys that have 30 to 55% aluminum. It is important to realize if the galvanized steel is struck hard enough, and the zinc coating is penetrated all the way down to the base steel, then the steel could spark of course. Source: Corrosion Resistance of Zinc and Zinc Alloys, by Frank Porter, pg. 97
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Can 4130 steel be successfully galvanized?

4130 steel is a chromoly steel. Steels of this chemistry have presented some adherence problems in the past when galvanized. The galvanized coating developed in some areas but not others. It would be best to try galvanizing a small sample of steel with this chemistry to determine the results before attempting to galvanize a large structure....
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Hydrogen Embrittlement

Hydrogen embrittlement occurs when steel cracks due to hydrogen that is trapped between the grains of the steel. Although steel commonly absorbs hydrogen during the hot-dip galvanizing process, it is usually expelled due to the temperature of the zinc in the galvanizing kettle. In some cases, however, the grain size of the steel is too small to a...
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Bracing (temporary and permanent) of steel fabrications for galvanizing

Most fabrications lend themselves well to the galvanizing process, including asymmetrical designs or structures containing sections of unequal thickness. It is important to understand that, because during galvanizing steel is exposed to temperature variations, fabrications of asymmetrical design or with sections of unequal thickness can exhibit different thermal expansion and contraction stresses, leading to changes in shape and/or alignment...
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Methods to Reduce the Occurrence of Strain-Age Embrittlement

There are several ways to reduce the occurrence of strain-age embrittlement, but all methods focus on one aspect – reducing the stresses induced into the steel prior to galvanizing. Instead of cold working, which induces stresses into steel, the steel can be hot worked at temperatures between 1100F and 1300F. If it is necessary to cold work the steel,...
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Why is steel chemistry important in the hot-dip galvanizing process?

Galvanized coatings are formed by a chemical process during which steel and zinc metallurgically bond, forming a series of corrosion-inhibiting, highly abrasion-resistant zinc/iron alloy layers. Galvanized coatings are specified for their corrosion resistance. While a gray or matte appearance may occur, the corrosion protection afforded is no different than that provided by shinier galvanized coatings. The corrosion resistance of matte...
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How much does galvanizing cost?

Due to the relatively stable price of zinc and technology /process efficiencies in the last 20 years, hot-dip galvanizing has steadily become more competitive, and often less expensive, on an initial basis than other corrosion protection systems. To compare the cost of hot-dip galvanizing to other protective coatings, please use the online
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