Carbon steel castings

Carbon steel

It is important to clarify the meaning of carbon steel in the generic sense and in the more narrow context used in this report. The term steel is usually taken to mean an iron-based alloy containing carbon in amounts less than about 2%. Carbon steels (sometimes also termed plain carbon steels, ordinary steels, or straight carbon steels) can be defined as steels that contain only residual amounts of elements other than carbon, except those (such as silicon and aluminum) added for deoxidation and those (such as manganese and cerium) added to counteract certain deleterious effects of residual sulfur. However, silicon and manganese can be added in amounts greater than those required strictly to meet these criteria so that arbitrary upper limits for these elements have to be set; usually, 0.60% for silicon and 1.65% for manganese are accepted as the limits for carbon steel.

The carbon steels of interest in this report are those with carbon equal to or less than about 0.35% to facilitate welding. A further distinction can be made according to carbon content.

1. Low-carbon steels (below 0.15% carbon) contain too little carbon to benefit from hardening and are frequently used in the hot-worked or—for maximum ductility—the annealed condition. Steels of less than 0.25% carbon (often referred to as mild steel) have somewhat higher strength near the upper carbon level.
2. Medium-carbon steels (0.25–0.55% carbon) are often heat-treated (quenched and tempered) to achieve yet higher strength, but it is mainly the compositions below 0.35% carbon that are relevant to this report. Carbon steel is one of the most widely used materials in the industry. This material is used not only in many of the water- and steam-pressure containing systems in power plants but also in the supports for these systems. Although this report concentrates primarily on the pressure containing applications of carbon steels, it can also be a useful tool for structural carbon steel fabrication issues.

As the description implies, the primary alloying element of these iron based materials is carbon. Because carbon is such a powerful alloying element in steel, there are significant differences in the strength, hardness, and ductility achievable with relatively small variations in the levels of carbon in the composition. However, other important factors—such as material fabrication, heat treatment, component fabrication, and Introduction 1-2 fabrication processes—can result in significant changes to the properties of the carbon steel components.

In some cases, requirements established by codes and standards must be supplemented to achieve adequate results when working with carbon steels. It is important for the utility engineer to have access to metallurgical and properties information to aid in making decisions for projects involving carbon steels. This report is intended to provide such information on the most common boiler and piping materials used in power plants. Not all carbon steels will be covered explicitly, but the user should be able to draw relevant information needed for any required decision.

Investment Casting

The investment casting process is perfect to help our customers in investment casting to be able to make superior purchasing decisions.

Wax Injection :

Imitation of the preferred investment casting is created by injection molding or for lesser volumes using speedy prototyping (SLA or SLS). These mock-ups are referred to as patterns.

Assembly of Wax Tree :

Patterns are then fastened to a central wax stick, called a sprue, to form a casting. This is known as wax tree.

Ceramic Shell Building :

The shell is made by submerging the wax tree meeting in liquid ceramic slurry and then into a bed of fluidized fine sands. Up to eight coatings are applied in this way depending on the shape and weight of the part.

Dewax :

formerly the ceramic is dry; the wax is then liquefied out, making a negative impression of the meeting within the ceramic and sand shell. This process utilizes autoclaves to uphold shell reliability.

Conventional Casting :

In the conventional lost wax casting procedure, the pre-heated shell (up to 1800 deg F) is poured with molten metal by gravity filling the metal into the ceramic shell. As the metal cools, gates, sprue, the parts, and filling cup become one solid casting. Shell temperature and dissolving temperature will differ depending on the alloy.

Knockout :

once the metal is cooled and hard, the ceramic shell is wrecked off by tremor or water blasting.

Cut Off Of Parts :

The parts are then cut away from the central sprue utilizing an elevated speed saw.

Finished Metal Investment Castings :

Following minor finishing operations, or potential needed machining functions, the metal investment castings-identical to the innovative wax patterns--are prepared for shipment to the customer from our metal investment casting China foundry. We are able to offer finished cobalt alloy investment casting, steel investment casting, aluminum investment casting, stainless steel investment casting, nickel alloy investment casting and precision investment castings.

Wall Thickness :

Please call for tolerance stipulation for wall thickness or any tolerances in common. As per the metal or alloy, least amount of wall thickness can vary from 0.04 inches to 0.08 inches.

Advantages :

1. No flash or parting lines
2. Almost any metal can be cast.
3. Ready for use with little or no machining required.
4. Very close tolerances and excellence surface finish can be obtained.
5. Complex shapes which are complicated by any other technique are possible.
6. Suit for producing complex shapes where other production processes are too expensive and time-consuming.
7. Expensive as many labor engaged in the preparation of the wax patterns & shell moulds.