ASTM D6492 - 99(2016) - Standard Practice for Detection of Hexavalent Chromium On Zinc and Zinc/Aluminum Alloy Coated Steel

ASTM D6492 - 99(2016)

Standard Practice for Detection of Hexavalent Chromium On Zinc and Zinc/Aluminum Alloy Coated Steel

Status : Current   Published : April 2016

Format
PDF

Format
HARDCOPY



1.1 This practice can be used to detect the presence of hexavalent chromium on galvanized and zinc/aluminum alloy coated steel surfaces. Hexavalent chromium-bearing treatments (passivates) can be applied to coated steels to prevent storage stain. While passivated 55 % aluminum-zinc alloy coated steel is commonly painted, passivated galvanized steel is not. Chrome passivation may interfere with the successful pretreatment of galvanized steel, as well as contaminate cleaning and pretreatment baths on a coil coating line.

1.2 The amount of hexavalent chromium that will cause the indicator to produce a discernible pink color is in the range of 0.5 parts per million dissolved in the indicator solution. It is possible that a coated steel surface that produces a negative result does have chromium on the surface. If a material that yields a negative result is suspected of having chromium on the surface, instrumental methods should be used. Chrome deposits of 1 mg/ft 2 can be easily missed by analytical instruments such as the scanning electron microscope with energy dispersive x-ray analysis (EDXA) capability. Auger electron spectroscopy (AES) or electron spectroscopy for chemical analysis (ESCA) can identify chemical species present in the levels required for adequate detection. Stripping the metallic coating and analyzing for chrome by atomic absorption or inductively coupled plasma can also give reliable results in detecting the presence of chrome.

1.3 This practice is designed to be a qualitative means of screening chrome passivated coils from those which are not chrome passivated.

1.4 Some chromium-free passivates are being used commercially. Although these products will test negative for hexavalent chromium, they may interfere with cleaning and pretreating. Chromium bearing passivates that contain film forming constituents such as acrylic resins are also being commercially applied. The reaction of these products to the spot test will vary. Abrading the surface with emery paper will improve the likelihood of reliable detection. This technique is not recommended for acrylic resin containing passivation treatments.

1.5 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.

1.6  This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.




Standard NumberASTM D6492 - 99(2016)
TitleStandard Practice for Detection of Hexavalent Chromium On Zinc and Zinc/Aluminum Alloy Coated Steel
StatusCurrent
Publication Date01 April 2016
Normative References(Required to achieve compliance to this standard)No other standards are normatively referenced
Informative References(Provided for Information)No other standards are informatively referenced
Descriptors Diphenylcarbohydrazide, Hexavalent chromium, Passivate, Passivation, Steel, Zinc, Zinc/aluminum
ICS25.220.40
PublisherASTM
FormatA4
DeliveryYes
Pages2
File Size53 KB
Price£36.00


 Your basket
Your basket is empty

Multi-user access to over 3,500 medical device standards, regulations, expert commentaries and other documents


Tracked Changes

Understand the changes made to a standard with our new Tracked Changes version


Collaborate, Innovate, Accelerate.


BSOL

The faster, easier way to work with standards