Pickling and Passivation Bath
At International Corrosion Services, we believe in providing superior services, which is why we have invested in a high technology stainless steel pickling and passivation bath, the largest and best of its kind in Australia. The bath and process systems ensure all stainless steel is pickled and passivated in full compliance to ASTM A380, ASTM A967 and AS 1627.1 and AS 1627.5. All treated stainless steel is supplied with a certificate of conformity to the relevant standards.
International Corrosion Services’ premise has all of the regulatory license and permits, which allows us to use hydrofluoric and nitric acid suitable for most commercial grades of stainless.
Under ASTM A380 and AS1627 there is much misinformation about what chemicals can be used to effectively pickle. There is no doubt from the research and our vast experience that the best method to descale and remove heat affected zones including heat tint is an effective concentration of hydrofluoric acid. Many companies purport that their propriety mixes are just as effective but we have found that this is not the case. International Corrosion Services unique system relies on nitric or a similar oxidizer that is then used to passivate the stainless steel and reform the chromium oxide layer.
This system is unique to Australia and features of the International Corrosion Services Pickling & Passivation bath include:
- Mixer for circulation of the pickling bath.
- Temperature sensor.
- Electrical heaters.
- Electrical control panel and control units.
- Bath cover/lid (manual handling).
- Fumes exhaust system.
- Chemical filtration.
- Waste Disposal and recycling system.
- 10 tonne and 5 tonne overhead cranes.
Our process system, purchased from Sweden, ensures the customer the best possible pickle and passivation treatment in full compliance with the standards.
When to Pickle and Passivate your Stainless Steel?
Pickle & passivation of your stainless steel should be done for post weld treatment and further to that to ensure it is clean from contaminants to ensure you give it has its best chance of resisting corrosion.
What is pickle and passivation of stainless steel and why do we treat it?
Stainless steel performs at its optimum corrosion resistance when it is kept clean so it can self passivate which is a thin layer of chromium oxide which generates itself due to the metal composition of the stainless steel. In essence the AS 1627, ASTM A380 and ASTM A967 processes are all about cleaning the entire surfaces of the stainless steel inside and out to ensure its optimal corrosion resistance.
Stainless Steel has a extremely thin chromium oxide layer commonly called a passive layer, which gives it the corrosion resistant properties it is so well known for. However after welding stainless steel the self passivating properties of the stainless steel are destroyed and the stainless steel cannot reform a chromium oxide layer. The damaged areas caused by the welding are commonly called the heat effected zone. This leaves the stainless steel susceptible to corrosion if left untreated.
It has been well known that Pickling by the use of Hydroflouric acid removes the damaged layer of stainless steel revealing a fresh untainted layer thus allowing it to reform the chromium oxide layer. Although stainless steel does self passivate after 24 to 48 hours the passive layer is instantaneously formed using Nitric acid or other oxidisers. ASTM A380 specifies that Nitric acid can be used to descale but it is no where near effective as using Hydrofluoric acid in removing the damaged layer of stainless steel in the heat effected zone.
Why pickle and passivate using the ICS bath, spray pickling booth or Avesta Finishing Chemicals?
ICS has the largest pickle and passivation bath in Western Australia. By using the ICS pickle and passivation process it ensures your welds post fabrication are treated inside and out so that it restores the stainless steel to allow it to passivate.
It also ensures that as part of the process all of the surfaces are cleaned from oils, greases, dust and dirt, which gives the stainless steel its best chance of withstanding corrosion.
Our pickle and passivation process is tried and proven and is in full compliance to the ASTM A380, ASTM A967, AS1627.1 & 1627.5.