Re: stainless steel bolts

On 11/8/2024 10:10 AM, Larry Wolff wrote:

On 11/7/2024 12:48 PM, Clare Snyder wrote:
 

   cheap-assed chinese electro-zinc plated grade 2 would be my guess.
What markings *(if any) on the head?

 I never thought of looking at the head of the bolt, which does have soem
"secret code" written on it as you can see in the photo of the head here.
https://i.postimg.cc/t4NwLb2V/qj4-8-bolts.jpg
 What do those strange markings mean to you? "Q J 4.8."

Grade 4.8 is a standard for fasteners like bolts, screws, and studs, which are made from low or medium carbon alloy steel. The numbers on fasteners, such as 4.8, 8.8, 10.9, or 12.9, indicate the tensile strength in the first digit and the yield strength in the second digit.
Here are some characteristics of Grade 4.8 fasteners:
Tensile strength: For low carbon steel, the tensile strength is around 420 Mpa, and for medium carbon steel, it's around 500 Mpa.
Core hardness: The core hardness is between B71–95 on the Rockwell scale.
Size range: The size range for a fully or partially annealed Grade 4.8 screw is between M5 to M100.
Uses: Grade 4.8 fasteners are used in mechanical equipment, buildings, bridges, tunnels, and high speed railways.
Strength: Grade 4.8 bolts are commonly referred to as high strength bolts.