{"id":22121,"date":"2023-09-28T14:01:24","date_gmt":"2023-09-28T11:01:24","guid":{"rendered":"https:\/\/fractory.com\/?p=22121"},"modified":"2024-01-31T13:35:27","modified_gmt":"2024-01-31T11:35:27","slug":"metal-pickling-explained","status":"publish","type":"post","link":"https:\/\/fractory.com\/metal-pickling-explained\/","title":{"rendered":"Pickling Explained – Definition, Process & More"},"content":{"rendered":"

Many manufacturing processes leave residues on metal surfaces that must be cleaned before further processing or prior to putting the metal parts into use. These surface impurities can exist in the form of metal oxides, stains, rust and other contaminants.<\/span><\/p>\n

Processes such as grinding, abrasive blasting<\/a>, or wire brushing are often used to achieve these objectives. However, these processes can be less accurate and may either remove excessive or insufficient amounts of metal at times. <\/span><\/p>\n

In this article, we shall explore an alternative, a more reliable surface finishing<\/a> process known as pickling, which is commonly used to remove scale and rust from metal surfaces. Let\u2019s begin.\u00a0<\/span><\/p>\n

What Is Metal Pickling?<\/span><\/strong><\/h2>\n

Metal pickling is the process of cleaning contaminated metal surfaces with specific chemicals before further processing or coating.<\/span><\/strong> It is most commonly performed after <\/span>hot working processes since they tend to leave a discolored oxide layer on the surface. To remove this scale, the workpiece is immersed in acid baths. Thus, prior to cold rolling operations, hot rolled steel usually goes through a pickling line to remove surface scale.<\/p>\n

Different metals and applications use various acids but the most common ones are hydrochloric acid and sulphuric acid. Since the chemicals used are commonly known as <\/span>pickle liquor<\/span><\/strong>, the process came to be known as pickling. It is sometimes referred to as acid washing if descaling is not needed. <\/span><\/p>\n

The metal parts are exposed to the pickling liquids through immersion bath, spray, or application with a brush. In the case of pipes that need to be pickled internally, the pickling liquid is pumped through them.\u00a0\u00a0<\/span><\/p>\n

Pickling is most often performed on ferrous metals<\/a>, noble metals, copper and aluminium alloys<\/a>. Pickled metal has various benefits such as an attractive surface, increased durability, increased corrosion resistance, and removal of heat-affected zones<\/a>.<\/span><\/p>\n

Pickling Process – How Is Steel Pickled?<\/span><\/strong><\/h2>\n

The pickling process is pretty straightforward and it can be divided into six simple stages:<\/span><\/p>\n

    \n
  1. \n

    Pre-cleaning<\/span><\/p>\n<\/li>\n

  2. \n

    Pickling solution preparation<\/span><\/p>\n<\/li>\n

  3. \n

    Pickling<\/span><\/p>\n<\/li>\n

  4. \n

    Rinsing<\/span><\/p>\n<\/li>\n

  5. \n

    Neutralisation and rust inhibitor application<\/span><\/p>\n<\/li>\n

  6. \n

    Drying<\/span><\/p>\n<\/li>\n<\/ol>\n

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    \n
    \n<\/span>