Hook SteeL

A Dutch boat yard certificate of construction states that the hull was made from

"Hook Steel" -

Questions :- what is hook steel ? Does it have special characteristics ?

 

After some extensive searching on the web I came across this for "Hook Steel".

It may or not be correct, but it sounds as if it could be right.

Allegheny Ludlum AL 304DA is tri-ply composite consisting of a dual stabilized, low carbon steel center "sandwiched" between Type 304 stainless steel. The top and bottom stainless steel surfaces (cladding), each representing approximately 20% of the product thickness, are bonded to the carbon steel core during hot rolling, thereby providing a metallurgical bond which remains sound during subsequent cold forming operations. This composite product provides the excellent corrosion resistance of AL 304 stainless steel along with the good heat transfer characteristics of carbon steel. Carbon from the core does not migrate into the stainless steel cladding during hot processing and thereby enhances formability by eliminating the possibility of "hook cracks" caused by carbide precipitation at the stainless/carbon steel interface.

 

Sounds remarkably similar in concept to the Novelis "Fusion Technology" line of aluminum alloy sheet... multiple layers formed into a single sheet during hot rolling, the result has the surface properties of one alloy with the structural properties of another.
As to the original question, I've never heard the term "hook steel" in this sense, and so can't tell you what exactly it means.

 

When was the vessel constructed ?

 

Hello Mike Johns and to Kessica,

Thanks for coming back, I managed to get a copy of the copy of the original Builder's cert for the hull which was built in 1970.

The 1977 reference to HOOK-STEEL in the copy of the 1970/73 certificate is the direct English translation of the Dutch words :-

" Hoek-Staal" = Corner-Steel, which is ANGLE Iron in our terms


50mm one side x 30mm the other side x 5mm thick. ( 2" x 1 ¼" x 5mm thick) which are frames set every 16½ " apart.

The Allegheny Ludlum AL 304DA is tri-ply composite consisting of a dual stabilized, low carbon steel center "sandwiched" between Type 304 stainless steel - this is steel used in pots and pans - they don't make angle iron.

Thanks every one.