44W - HSLA - High Strength Low Alloy steel coming into common usage in Canada beginning in the early 1980s, this material has become the most popular structural steel steel in use in Canada. When we say "mild steel" around IMAC, it is this HSLA that we are referring to. Like A36, it is not recommended where low temperature toughness is important. 44W can be flame cut, formed, drilled, welded and machined by all normal means.
Like A36 the 44 designation refers to the yield strenght.
Fu is 65 ksi. Fu for CSA G40.21M-Grade 300W is 450 to 620 MPa, (so 65 ksi is the lower bound). The 300 is the yield in MPa (43.5 ksi, but historically was 44 ksi). Note that the yield of 300 MPa applies up to 65 mm plate and drops to 280 MPa above that thickness (plate greater than 65mm, is still called 300W, even though its yield is 280 MPa). In Canada, this material is still in use for plate, as 350W is not as readily available. Rolled wide flanges are normally 350W.
