In the polyethylene industry, there are various types of fittings, and one of them is the classification of welded polyethylene fittings. However, it might be better to say that this naming is actually a common mistake in the polyethylene industry.

This is because welded polyethylene fittings do not refer only to a specific type of fitting; instead, they encompass a collection of all injection-molded polyethylene fittings, handmade (miter) fittings, and branched polyethylene fittings, all of which share the common feature of using the butt-welding technique to connect polyethylene pipes to each other.

Generally speaking, it can be said that welded polyethylene fittings are the most commonly used polyethylene fittings and meet the needs of a very wide range of polyethylene projects.

Comparison of the Production Methods of Different Welded Polyethylene Fittings

As we have understood, welded polyethylene fittings include injection-molded fittings, handmade (miter) fittings, and branched fittings, each having its specific production process.

Welded polyethylene fittings of the injection type are produced using heavy HDPE100 polyethylene granules. In their production process, a plastic injection machine and pre-made steel molds are utilized.

If the raw materials used in the production line are colorless (natural), they should be mixed with black masterbatch; however, if self-colored (black) granules are used in the production line, there is no need to add any additives.

On the other hand, both handmade (miter) fittings and branched polyethylene fittings are produced using polyethylene pipe, with the difference that the butt-welding machine is used for the production of handmade fittings, while the saddle welding machine is used for branched fittings.

Types, Sizes, and Working Pressures of Different Welded Polyethylene Fittings

Injection-molded polyethylene fittings are very diverse among the collection of welded polyethylene fittings, including various types such as flanges (regular and type B), tees, reducers (concentric and eccentric), elbows, polyethylene caps, terminal water valves, crosses, blank polyethylene flanges, and steel rings with reinforced polymer coatings.

Concentric and eccentric reducers, regular and type B flanges, polyethylene caps, and blank polyethylene flanges are produced in working pressures of 6, 10, 16, and 20 bars and sizes ranging from 63 to 1200 millimeters.

Elbows and tees are available in small sizes from 63 to 500 millimeters and working pressures of 6, 10, 16, and 20 bars.

The terminal water valve is offered to customers at a working pressure of 4 bars and in a size of 160 millimeters.

The steel ring with a reinforced polymer coating is produced for working pressures of 10 and 16 bars or class 150, ranging in size from 63 to 315 millimeters.

In contrast, handmade (miter) fittings and branched polyethylene fittings as another subset of welded polyethylene fittings do not have a wide variety of types, but because they utilize polyethylene pipe in their production process, they offer a very high diversity in size, working pressure, and angle needed for production that is not repeated in any other type of fittings.

Types of handmade (miter) fittings include: tees, elbows, crosses, collectors, and custom fittings.

Branched polyethylene fittings also include branched tees.

Elbows are produced in sizes from 63 to 1200 millimeters, at angles from 8 to 90 degrees, and with working pressures ranging from 6 to 25 bars. Tees are produced in sizes from 63 to 1200 millimeters, with working pressures of 6 to 25 bars and angles of 45, 60, and 90 degrees and are available in the market.

Comparison of the Characteristics of Different Welded Polyethylene Fittings

Variety of fittings: Welded polyethylene fittings of the injection type are very diverse in terms of the different types produced, while handmade and branched fittings have a high diversity in size, working pressure, and angle.

Weight of fittings: Welded polyethylene fittings (of the injection type) are very lightweight, making them easy to transport and install.

Production speed: While it is true that injection fittings require preparation for the steel molds initially, once these molds are made, the speed of production for injection fittings is very high, allowing for a high volume to be produced in a shorter period.

However, handmade (miter) and branched fittings may face delays in progressing their production plans due to reliance on the availability of polyethylene pipe (which is produced in other factories).

Price: Injection-molded polyethylene fittings are much more cost-effective than handmade (miter) and branched fittings.

Weld bead: Injection-type welded polyethylene fittings have a monolithic structure, and there are no weld beads in their structure. However, the structure of handmade (miter) fittings is multi-pieced, and the presence of weld beads can expose them to potential damage.

Reduction factor: The most important feature of injection-molded polyethylene fittings is that they are not required to follow a reduction factor. In contrast, for producing handmade (miter) fittings, adherence to the reduction factor is stated in the standard documentation.

What costs should be considered for producing welded polyethylene fittings?

As we know, handmade and branched welded polyethylene fittings are produced using polyethylene pipe, and the costs associated with their production include:

Sourcing high-quality polyethylene pipe from reputable pipe manufacturers

Purchasing standard cutting machines and saws for cutting pipes at the correct angles

Acquiring butt welding and saddle welding machines for producing handmade (miter) and branched fittings, respectively

Hiring skilled and experienced welders and cutters

Other ancillary costs considered as labor costs.

In contrast, the costs involved in producing injection-type welded polyethylene fittings are different and include the following:

Purchasing a plastic injection machine

Acquiring the necessary steel molds for separately producing each fitting

Buying HDPE100 heavy polyethylene raw materials from the stock market

Purchasing black masterbatch (if the raw materials are not self-colored)

Hiring trained and skilled operators

And generally, overhead costs considered for producing any product.

With all these considerations, it should be noted that the final selling price of handmade (miter) and branched polyethylene fittings is higher than that of injection-molded polyethylene fittings, as handmade and branched fittings are always larger in size compared to their similarly sized injection-molded counterparts.

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