Half Coupling vs. Weldolet

First, don't use all caps! Caps = shouting.

You did not say what size pipe you are puting these connections on. I will assume that you are talking about a medium to large size ( 4" to 10").

I recommend that you use Sock-O-Lets. They initially cost a little more than the 6000# coupling but you will spend the difference in labor trying to shape the end to fit the pipe and the bevel for the weld.

Use weld o lets that's what there designed for \.

Thank you for the reply. The pipe size is 16" and material is P-91. Please read sockolet instead of Weldolet in my query.

Other than cost & labour work is there any difference in strenght of half coupling & sockolet.

All fittings which used in branch connections and belong to "O-Let Family" (my nomination) are being welded to the main run using a groove weld (preferred more than fillet weld). That is means that both Weldolet and Sockolet are welded to the main run by groove weld. The difference between Weldolet and Sockolet is the other end connection, where in Sockolet it will be welded by socket weld (fillet-weld), and in Weldolet it will welded by groove weld (butt-weld) which is recommended.

O-Let family such as Weldolet, Sockolet, Threadolet, Elbowlet, latrolet and Nipolet are characterized by its base connection having a contour with a curvature adapted with the curvature of the main run, and welded into the main run by groove weld followed by a fillet weld, which we are strongly recommend for piping systems with a relatively higher pressures and temperatures.

what is the minimum fillet size in weldolet?

question - if i were to reply to this question and i chose to use all small letters, am i whispering?

No,

_{subscripts would be wispering}

For piping systems with relatively higher pressures and temperatures, we prefer and recommend using the butt-welded fittings (groove welds) such as weldolets, and we don't recommend using socket-welded fitting (fillet weld). The strength of certain fillet weld joint resists 1/3 the strength of butt weld joint.

The socket weld half coupling is not joined using fillet weld. The socket weld is the connection type at other end of coupling. The coupling is joined with run pipe by full penetration weld.

I know exactly what do you mean, but if you insist to use half coupling, I prefer to use the coupling to be "set-in" (not set-on). This means that you will open a hole in the pipe with a diameter greater than the OD of the half coupling (with sufficient root opening which depends on the type of weld process used), and such a beveling (V) shall be made and the coupling will be welded using full penetration (groove weld), followed by fillet weld.

Notes:

1. The selected rating/class of coupling (3000#, 6000# or 9000#) must be matched with the pipe schedule in which it will be assembled.

2. Take care for the excessive protrude of half coupling inside the piping system to avoid obstruction with pigs/scrapers (if any).

Strictly from a welding point of view a saddle-in is easier to get a full penetration weld than a saddle-on and not have mistakes in the finished weld although if done correctly both can be full pen. welds. I am talking about the angle of bevel on the high side of the header where it is a tighter fit and thus harder to get the root to "break down" or melt both the wall of the branch and header. On saddle-in type fit ups the angle of bevel will be nearly the same all around and much easier to see and weld as well IMO. No matter what type of fitting one decides to use the branch contour should fit the header in a fashion that there is no penetration of the branch line into the header. This is especially important with steam, condensate and acid piping or any other service that excessive turbulence is to be avoided also IMO.

pipewelder

The rule I follow for steam pipe is that I would only use a weld-o-let or tee and reducer. In the mill I work in it is required to use a sock-o-Let or weld-o-let or tee on steam branches of any size as compared to half couplings or saddles. If a saddle has to be used then you should do calculations as to what size reinforcement pad is required. We have specs that clearly state this and also have tables that give you reinforcement plate sizes for all piping services. Weld-o-lets are engineered to have the reinforcement made into them from the factory thus eliminating the need for extra reinforcement. Also at the mill I work at bolts are not allowed to be used on steam pipe flanges and we only use heat treated B7 studs that are clearly stamped with identification as well as the matching alloy nuts.

pipewelder

GIRIDHAR

USE ONLY 6000# SW HALF COUPLING IS BETTER FOR YOUR REQUIREMENT