Flange style
Thread Content
The conditions specified for procurement are as follows: threaded union fittings (55° pipe thread), TUN-Rc per GB/T32294. Two 1-inch union fittings were purchased, both made of 304 material. The PJ variant is considered to have better quality but is also more expensive. What does PJ mean? In the context of flanges, PJ seems to refer to a loose-flange type. What are the differences between these two types of union fittings?
GB32294 applies to forged socket-weld and threaded union fittings; so which of these two pictures falls under this standard?
The first image looks like it’s galvanized.
The material is also 304; it appears to be cast, while the one below looks much smoother and is likely machine-finished. It’s not clear which one meets the specifications, or if neither of them does
There are several standards for stainless steel union fittings, and legitimate products should indicate the standard number.
The standard number for purchasing these is GB32294. The two versions purchased are different – they are the ones shown in the pictures – and their prices vary significantly. I’m not sure which one is correct; which one falls under standard 32294?
GB32294 specifies that the standard number must be indicated on the product’s steel stamp; neither of the two photos shows such a standard number, so neither product meets the GB32294 standards.