Black steel pipe fittings and galvanized steel pipe fittings are the two most common kind of pipe applied to transport liquid and gas. Both black steel pipe and galvanized pipe are made of steel, however, galvanized pipe has a zinc coating while black pipe does not. As a result galvanized pipe is more durable. For transportation, black steel pipe tend to erode more easily than galvanized pipe and therefore it is more suitable for transporting gas and galvanized pipe is fit for carrying water instead of gas.
Galvanized pipe fittings are covered with a layer of zinc which makes these fittings have higher ability of corrosion protection and help to prevent the accumulation of mineral deposits that will block the pipe. Galvanized pipe is mainly used for carrying water to supply home and commercial buildings; it may also serve as scaffolding frames because of its rust prevention.
Galvanized pipe fittings are used for countless outdoor and industrial applications because of the material's ability to protect against corrosion and salt. Galvanized pipe and fittings may be used in most applications with the exception of underground lines. While they work best with cold water lines, they may be used with hot water as well. The main advantage of using galvanized fittings is their superior rust resistance when compared to black and copper fittings. Galvanized pipe fittings should not be used with gas applications.
Black pipe fittings (black malleable iron fittings) are used to make connections to black iron pipe. Black iron pipe is used to transport natural and propane gas in residential applications.
Black steel pipe is manufactured as seamless which makes it a better type for gas transportation and fire sprinkler systems since it can prevent fire better than galvanized pipe. Black iron pipe is also most often use in fire sprinkler systems due to its high heat resistance and for water supply lines due to its resistance to water damage. Since it has a dark color surface which is formed by iron oxide during the manufacturing process, it is called black steel pipe.
The main difference between steel pipe and galvanized pipe lies in the surface. Black steel pipe is uncoated and made without steam, and therefore, it is widely used for transporting gas like propane and natural gas to residential and commercial building.
Galvanized pipe has zinc on the surface so the mineral will flack off as time goes by and block the pipe. This will lead to a burst. In view of this, transport gas by galvanized pipes is dangerous so it is often used in carrying water.
Black steel pipe, on the other hand, is not suitable for water transport. Black steel pipes tend to corrode in water and mineral of the pipe will dissolve into the water and clog the line as well.
What Are Malleable Iron Pipe Fittings?
Malleable iron pipe fittings hold two different pipe parts together and direct the gas and liquid movement. Some malleable pipe fittings are threaded, meaning that they have grooved ends that allow plumbers to screw the pipe fittings on the pipes, letting plumbers connect different pipes together.
Composition
Malleable iron pipe fittings can come in black and galvanized finishes. The three forms of malleable cast iron include whiteheart, blackheart and pearlitic malleable cast iron. The surface zone of the whiteheart malleable cast iron has ferrite. The intermediate zone has temper carbon, ferrite and pearlite. Tempering refers to the hardening of metal. Blackheart malleable cast iron is mostly made of ferrite. The pearlitic malleable cast iron is made from pearlite and other austenite products. Pearlite is made from alternating layers of ferrite and cementite.
Types
Malleable pipe fittings come in a variety of shapes, depending on the applications that the plumber will use the fittings for. These shapes can include the elbow, a fitting that curves to send the pipe in certain direction. Another pipe fitting type, the side outlet elbow, is like the regular elbow, but has an added side outlet. The tee has three openings, with two on both ends of the pipe and one on one the side. The side outlet tees have four openings, one that is the side outlet. The cross has four openings, with each opening having a corresponding opening on the other side. These different fittings allow the plumber to send pipes in different directions and let pipes feed into each other.
Malleable Iron
Malleable cast iron is an alloy of iron carbon that engineers treat with heat. When first cast, the iron does not have any graphite. All the carbon content is in cementite form. Malleable iron typically has 2 to 3 percent carbon, 1 to 2 percent silicone, 0 to 1 percent manganese and small amounts of sulfur and phosphorus. Malleable iron has a high toughness due to its nodular graphite and the low-carbon content. Graphite forms in a way that makes the graphite not spherical but irregularly shaped.
Machinability
Engineers prefer malleable iron for parts that need to be coined, pierced or cold-formed. Cold forming refers to the process of rolling or pressing thin gauges of steel sheet into usable materials. Malleable iron works well for parts that need to have the most machinability, meaning the parts are easy to make using a machine. It also works well with pieces that need to resist impact under cold temperatures.
Intro to Black Iron Pipe Fittings
Black iron pipe is strong, and despite its name, it is actually made of a low-grade “mild steel” compound, not iron. This steel allows the pipe, and its fittings, to have more strength than its copper, aluminum, or PVC counterparts. It is commonly used to transport gas as the extra strength in this metal pipe could be what keeps potentially deadly gas from leaking throughout a home!
What’s an NPT Thread?
While black iron is a low-pressure pipe, the temperature rating is where this metal really shines. The black iron pipe can withstand temperatures of over 538°C and black iron pipe fittings are NPT threaded. Well, NPT stands for National Pipe Tapered, and NPT fittings seal by a wedging action, which makes for an easy installation.
Three Main Types of Black Iron Pipe Fittings
Here at ohcanadasupply.ca, we carry three types of black iron pipe fittings; malleable iron, forged steel, and seamless fittings.
Malleable iron fittings are made for light industrial and plumbing use up to 300psi. These common fittings are more ductile, which means that they are able to be deformed without losing toughness or becoming brittle. This makes them great for industrial use.
Forged fittings are made of carbon steel, stainless steel, or nickel alloy. The forging process involves heating a piece of carbon steel and molding it into the desired shape, which creates a stronger fitting than casting. Forging actually changes the structure of the steel, specifically the steel grain. Altering the grain flow in fact makes it tighter, which creates a metal that has greater impact and shear strength.
Lastly, we have Seamless fittings. These fittings are made directly from a section of seamless pipe material by applying heat and pressure. Their design allows them to withstand greater pressures and they won’t crack under an extreme load. Since there are no welded parts, these fittings are perfect for use in the oil and gas, chemical, plumbing, and fabrication industries!
Ways to Seal Black Iron Pipe
NPT black iron pipe seal through a wedging action, but they also need a sealant to create a leak-proof seal. Luckily, sealing tape and pipe sealant are inexpensive and easy to apply! But, be careful you need to be sure you’re selecting a sealant that’s compatible with whatever material you’re moving through the pipe.
Sealing tape, commonly referred to as “Teflon Tape” or “PTFE” tape, is a simple way to seal joints without making a mess. PTFE can only withstand temperatures up to 260°C, but that’s more than enough to handle anything nature can throw at it. But best of all, it only takes a few seconds to apply.
Your other option is a pipe sealant, also known as “joint compound” or “pipe dope.” This is a liquid sealant that oozes between threads to maintain a tight seal. Pipe sealant lubricates while it fills in all the microscopic imperfections in a thread. However, the downside to pipe sealant is that it can be quite messy compared to sealing tape.
What are Pipe Nipples?
Pipe nipples are often used in plumping and other hydraulic applications as adaptors. A pipe nipple is a length of straight pipe with male threads on both ends, as opposed to most fittings or pipes, which have one end with male, or external threads and the other with female, internal threads. Although you may be familiar with the standard barrel nipple, did you know that there are actually several different types of pipe nipples? A shortlist includes close, hex, hose, and welding nipples. There are, of course, more types out there, but these are the most commonly found.
Different Types of Pipe Nipples
Barrel Nipple
The most basic type, a barrel nipple, is a short length of pipe with male pipe threads at both ends. These threads are for connecting other fittings. For instance, the connection between the pipes in your wall and the shut-off valve under your sink is most likely a barrel-style pipe nipple! These nipples can range anywhere from 1-1/2” to 60” long, not including the threads.
Close Nipple
If you have a nipple but there is no bare or unthreaded pipe between the two connecting ends, you know you’ve got a closed nipple. With closed nipples, the connected fittings come very close to touching one another and barely any of the nipples can be seen between them. Some construction sites require this kind of tight placement, but sometimes, close nipples can be difficult to work with. This is because unscrewing them requires a tight hold on part of the threaded area, which will damage the threads. That’s why some industries, such as oil and gas, where these nipples are being used for intense applications, don’t allow the use of closed nipples. However, for job sites where closed nipples are used often, an internal pipe wrench is a great investment.
Hexagonal Nipple
If you can spare a bit of room between the threaded ends on your nipple, you may choose to use a hexagonal nipple. Hex nipples have a hexagonal section in the middle, which works just like a nut. This means that you can grip it with a wrench and torque, tighten, or loosen it much more easily than a normal, rounded pipe.
Threaded Nipple
The rounded cap that’s used to plug the end of a pipe or pipeline section is called a bull plug. This threaded nipple has a rounded, closed-end to seal off a pipe. These plugs are usually found on unfinished pipelines to keep dust and moisture, but they can also be used as an isolation device in piping systems.
Hose Nipple
The next nipple is a bit different and that’s because it’s made specifically for hydraulic applications. A hose nipple, which is a specialty nipple designed for hoses that require connection to a pipe. These are commonly found in low-pressure hydraulic systems since the hose barb connection doesn’t fare well in high-pressure applications. The barb on this fitting may be the same size as the pipe connection, or it might be smaller, depending on its usage.
Welding Nipple
Finally, there’s the welding nipple. This variant has a threaded connection on one end, and a beveled pipe on the other. The key to this nipple is in its name – the cut end is designed to be welded to piping, a fitting, or a tank. This allows for easy connection of pipes or other fittings once the unthreaded end has been welded to the surface of your choice. These are typically found in heavy-duty applications, like hydraulic presses, mining equipment, and steel mills.
What About Pipe Schedules?
One key point to keep in mind when choosing the correct pipe nipple is the pipe schedule. Pipe schedules relate to the thickness of the pipe wall and the most common schedules are 40 and 80. As the number increases, so does the wall thickness. For instance, a 1” schedule 40 pipe nipple will have a wall thickness of 0.133”, while a 1” schedule 80 pipe nipple will have a wall thickness of 0.179”. However, while the schedule number can be the same for pipe nipples with different outside diameters, the actual wall thickness will vary.
Pipe Schedules and Weights
So, the best way to see the relationship between nipple size, schedules, and wall thickness is to refer to a conversion chart! Another thing to keep in mind is that the nominal pipe size, or NPS, represents the approximate inside diameter of the pipe nipple. That’s because if the schedule number on size is changed, it affects the inside diameter, but not the outside diameter. For instance, a 2” nominal pipe nipple will always have an outside diameter of 2.375”, however, depending on the strength of the pipe nipple, the wall thickness could be either 0.154” or 0.218”.
We promise to provide you with competitive price tags, superior products and high-quality solutions, and fast delivery of Hot Dipped Galvanized Pipe Fittings,Toast Galvanized Pipe Fittings,Carbon Steel Pipe Nipple
