Effects of zinc coatings on the stress corrosion cracking and hydrogen embrittlement of low-alloy steel

Townsend, H. E.

doi:10.1007/bf02672311

Cited by 28 publications

(13 citation statements)

References 10 publications

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“…The IHE threshold is 0.85 Fu. The finding that the IHE threshold is significantly higher than the EHE threshold of 0.65 Fu for this material is in agreement with the findings of the 1975 publication [4].…”

Section: Phase 5 -2008 Rods At Pier E2 Tested In the Dry -Rods 18-19supporting

confidence: 92%

“…These results are significant because EHE thresholds for high-strength steels are known to increase as the electrode potential rises to less negative levels [4,5]. Figure 9 also shows that the electrode potential becomes less negative with time during the test.…”

Section: Test Resultsmentioning

confidence: 92%

“…The rate of loading is intended to be sufficiently slow to permit diffusion of hydrogen and slow crack growth, yet fast enough to allow testing to be completed within 24 days. The average rate of load increase shown in Table 2, up to 0.85 Fu, is approximately one-half that used to establish thresholds of one-inch square bars in the 1975 research [4]. In those cases, where the load reached 0.85 Fu, or when the onset of crack growth was suspected, the rods were held for six days.…”

Section: Test Protocolmentioning

confidence: 97%

“…The test is modeled after the work published in 1975 [4] to confirm Boyd and Hyler's earlier study of high-strength bolts [1]. The 1975 work evaluated the effects of galvanized coatings on thresholds for both internal hydrogen embrittlement (IHE) and environmentalhydrogenembrittlement(EHE)ofpre-cracked, quenched-and-tempered SAE 4140 steel bars.…”

Section: The Townsend Test and 1975 Workmentioning

confidence: 99%

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Hydrogen embrittlement testing and results of full-size ASTM A354 grade BD rods in the SFOBB

Townsend

Frank²,

Brignano

et al. 2016

BRS

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Abstract.To determine the hydrogen-embrittlement resistance of anchor rods in the new San Francisco-Oakland Bay Bridge, tensile tests of full-size ASTM A354 Grade BD anchor rods were conducted at very slow load rates. Resistance to embrittlement by hydrogen entering the rods while under load, also referred to as stress corrosion cracking (SCC) or environmental hydrogen embrittlement (EHE), was measured by performing the slow-load tests in 3.5% sodium chloride (NaCl) solution. Resistance to embrittlement by hydrogen entering the steel during fabrication processes such as hot-dip galvanizing, also referred to as internal hydrogen embrittlement (IHE), was measured by performing the slow-load tests in air. Testing was conducted on rods representing various sizes, different manufacturers, rolled and cut threads, different alloys, as well as galvanized and ungalvanized rods. Following slow-load hydrogen embrittlement tests, mechanical and chemical properties of the test rods were fully characterized, and fracture surfaces were examined by scanning electron and optical microscopy to establish modes of failure. The results of this work are discussed in terms of 1) material properties, such as strength level and hardness, and toughness; 2) processing variables, including galvanizing, and threading method; 3) the cause of failure of 32 anchor rods in March, 2013; and 4) establishment of safe loads for rods currently in service on the bridge.

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Section: Phase 5 -2008 Rods At Pier E2 Tested In the Dry -Rods 18-19supporting

confidence: 92%

Section: Test Resultsmentioning

confidence: 92%

Section: Test Protocolmentioning

confidence: 97%

Section: The Townsend Test and 1975 Workmentioning

confidence: 99%

See 2 more Smart Citations

Hydrogen embrittlement testing and results of full-size ASTM A354 grade BD rods in the SFOBB

Townsend

Frank²,

Brignano

et al. 2016

BRS

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“…[7][8][9][10] As metallurgy and the stresses are usually driven by the process, uncontrolled hydrogen charging must be avoided to obtain safe products, especially when a coating hinders hydrogen escaping from the steel. 11,12) Thermal desorption analysis, TDA, has been largely applied for the study of the diffusible hydrogen in bare iron and steels. [13][14][15][16] However, there is very little information available on the TDA analysis concerning the diffusible hydrogen content in the Al-Si coated steels.…”

Section: Introductionmentioning

confidence: 99%

Absorption/Desorption of Diffusible Hydrogen in Aluminized Boron Steel

Georges¹,

Sturel

Drillet

et al. 2013

ISIJ Int.

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Currently, boron steel with Al-Si coating experiences a rapid growth in the anti-intrusion applications in the car body due to its superior mechanical properties after hot stamping. However, the final microstructure can be sensitive to delayed fracture if the product is exposed to a critical combination of diffusible hydrogen content, stresses and other metallurgical factors. As the metallurgical parameters and stresses are usually defined, the proper control of the diffusible hydrogen content is the key parameter to improve the safety aspect of the product. However, this content is quite difficult to determine. In this paper, the parameters governing the absorption and desorption of diffusible hydrogen in aluminized boron steels is investigated. The present research shows that the dew point and the austenitizing holding time have a bigger influence on the diffusible hydrogen content than the austenitizing temperature. Simultaneously, four-point bending test, which is simple and representative of the stress field that may be encountered in car bodies, is used to determine the acceptable limit of the diffusible hydrogen amount. Using this test, a delayed fracture map is proposed, which can be used as a guideline to determine the safe process areas. The study reveals that fast cooling rates or the sheared edges lead to lower the critical diffusible hydrogen content. Nevertheless, under the standard industrial operating conditions, the materials remain safe. Finally, an e-coating process that is applied to the sample surface induces an efficient degassing that provides an additional safety margin.KEY WORDS: aluminizing boron steel; delayed fracture; hot stamping; diffusible hydrogen; bending test; thermal desorption analysis.

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Forms of Corrosion

Heidersbach¹

2010

Metallurgy and Corrosion Control in Oil and Gas Production

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Effects of zinc coatings on the stress corrosion cracking and hydrogen embrittlement of low-alloy steel

Cited by 28 publications

References 10 publications

Hydrogen embrittlement testing and results of full-size ASTM A354 grade BD rods in the SFOBB

Hydrogen embrittlement testing and results of full-size ASTM A354 grade BD rods in the SFOBB

Absorption/Desorption of Diffusible Hydrogen in Aluminized Boron Steel

Forms of Corrosion

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