China
Africa
Explore chapters and articles related to this topic
Consideration of the Role of Nb, Al and Trace Elements in Creep Resistance and Embrittlement Susceptibility of 9–12% Cr Steel
Published in A Strang, Performance of Bolting Materials in High Temperature Plant Applications, 2020
In the last formula, the equivalent carbon content (C + 12/14 N)was used and the ratio of interstitials in Nb(C,N) was assumed to be 1:1 [21]. The interaction parameters eCCr and eNCr were used in accordance with Kunze [26] in the form: eCCr=180/T+0.09eNCr=−145.8/T−0.056+0.017⋅log(T)
Machinability of Materials
Published in David A. Stephenson, John S. Agapiou, Metal Cutting Theory and Practice, 2018
David A. Stephenson, John S. Agapiou
Adding alloying elements to steel generally increases hardness in the as-rolled and annealed conditions, resulting in decreased machinability [153]. Many alloying elements are added to increase strength or wear resistance, and combine with carbon to form very hard, abrasive carbides, which reduce tool life; examples include chromium, nickel, and manganese [2]. Not surprisingly, the impact of alloying elements on machinability depends on the alloy content; low or lean alloy steels machine much more like carbon steels than corresponding high alloy grades [165]. A spheroidized structure in alloy steels results in improved overall machining performance because it reduces hardness and arranges the hard carbide phase into spheroids, which reduces the abrasive action of the carbides. Tempered alloy steels produce better surface finishes than annealed steels because the tempered structure reduces or eliminates BUE formation. As noted before, machinability tables can be used to assess the tool life to be expected from specific high alloy grades as compared to plain carbon grades. Formulas for computing an equivalent carbon content from the alloy content can also be used for this purpose [166]. A detailed discussion of the machinability of specific alloy families, related to their metallurgy, is given by Finn [153].
Steels
Published in M. Rashad Islam, Civil Engineering Materials, 2020
The ASTM A 6 specification prescribes the permissible maximum percentages of alloy elements, such as carbon, manganese, chromium, nickel, copper, molybdenum, vanadium, and so forth, in structural steel to ensure adequate weldability and resistance to corrosion and brittle fracture. In the specification, the percentage by weight of each of these chemical elements is combined to produce an equivalent percentage carbon content, which is called the carbon equivalent (CE). The carbon equivalent is useful in determining the weldability of older steels used in the repair or rehabilitation of existing or historical structures where the structural drawings and specifications are no longer available. It is also used for determining what, if any, special precautions are necessary for welding these steels in order to prevent brittle fractures. To ensure the good weldability already established above, the carbon equivalent, as calculated from Eq. 9.17, should be no greater than 0.5%. Precautionary measures for steels with higher carbon equivalents include preheating the steel and using low-hydrogen welding electrodes. Alternatively, bolted connections could be used in lieu of welding. The equivalent carbon content or carbon equivalent is given as shown in Eq. 9.17: CE=C+Cu+Ni15+Cr+Mo+V5+Mn+Si6≤0.5
The Effect of Heat Treatment on the Performance of Antiwear Steel Coatings Deposited on AISI 1015 Steel Substrates
Published in Tribology Transactions, 2021
Sandro C. Silva, Luiz L. Silva, Marcelo A. Câmara, Paulo César M. Rodrigues, Alexandre M. Abrão
The chemical composition of the substrates and coatings is given in Table 1. Although the iron content is similar for both materials, the carbon content in the coating is lower and the higher amounts of Mn and Si are expected to increase the toughness of the coating. The effect of the reduction in carbon content on the hardenability of the coatings is counterbalanced by the increase in magnesium and silicon contents, which elevate the equivalent carbon content to a value above the actual carbon content and ensure a satisfactory hardenability to the coating (9).
Determination of the optimum preheat temperature in hardfacing hypereutectoid steels
Published in Welding International, 2018
In the case of structural low-alloy steels this relationship can be applied using the criterion of the equivalent carbon content. In general practice, the carbon equivalent is determined by the following equation: