Top five aluminum extrusion companies in the world

As of my last knowledge update in September 2021, I can provide you with a list of five prominent aluminum extrusion companies in the world. 

Please note that rankings and company statuses may have changed since then, so it's advisable to verify this information for the most current data. Here are five well-known aluminum extrusion companies:

China Zhongwang Holdings Limited: China Zhongwang is one of the largest aluminum extrusion companies globally and is based in China. They have a wide range of extrusion products and serve various industries.

Norsk Hydro: Norsk Hydro, headquartered in Norway, is a major player in the global aluminum industry. They are involved in various aspects of the aluminum value chain, including extrusion.

Constellium: Constellium is a global manufacturer  aluminum extrusion manufacturer of aluminum products, including extrusions. They have operations in Europe, the United States, and other regions.

Alcoa Corporation: Alcoa, based in the United States, is a leading aluminum producer with a presence in the extrusion market. They have a diverse portfolio of aluminum products.

Kaiser Aluminum: Kaiser Aluminum is a U.S.-based company known for its expertise in aluminum extrusions and other aluminum products. They serve industries such as aerospace, automotive, and industrial.

Please keep in mind that the ranking and prominence of these companies may have changed since my last update, and there may be other significant players in the aluminum extrusion industry. It's a good idea to consult the latest industry reports or news sources for the most up-to-date information.