Percent Cold Work
Calculate the percent cold work (area reduction), %CW = (A₀ − A_f) ÷ A₀ × 100%, from the initial cross-section area A₀ and the final area A_f after cold plastic deformation (rolling, drawing, stamping). The result, in %, shows how much the material was deformed below the recrystallization temperature. Cold work strain-hardens the metal: it raises the yield strength and hardness and lowers ductility as dislocations multiply and tangle. It is the parameter used to control properties before an anneal. Enter the initial and final areas.
Result
—
Percentual de trabalho a frio
Trabalhar a frio um metal é deformá-lo plasticamente abaixo da sua temperatura de recristalização (laminação a frio, trefilação de arames, estampagem). A quantidade de trabalho a frio se mede pela redução de área: %TF = (A₀ − A_f) ÷ A₀ × 100%, comparando a seção transversal antes e depois da deformação. O efeito sobre as propriedades é profundo e se chama encruamento (ou endurecimento por deformação): à medida que o metal é deformado, as discordâncias (defeitos lineares da rede cristalina que permitem o escorregamento) se multiplicam e se emaranham, travando umas às outras. O resultado é que o limite de escoamento e a dureza aumentam, enquanto a ductilidade cai — o material fica mais forte, porém mais frágil e difícil de continuar conformando. Por isso o %TF é um parâmetro de controle de processo: define-se quanto encruar para atingir a resistência desejada, e quando é preciso fazer um recozimento intermediário (aquecimento que recristaliza o metal, apagando o encruamento) para poder continuar a deformação sem trincar. Informe as áreas inicial e final da seção.
Related Tools
Minimum Bend Radius
Estimate a sheet's minimum bend radius, R_min = t·(50/r − 1), from the thickness t (mm) and the material's percent reduction of area r in the tensile test (%, a ductility measure). The minimum radius is the smallest inner radius you can bend a sheet to WITHOUT cracking the outer face (which is in tension). Bending below the minimum causes cracks or rupture in the outer fiber, where tensile strain exceeds the material's capacity. The minimum radius depends strongly on the material's DUCTILITY (here via reduction of area r): very ductile materials (annealed aluminum, low-carbon steels) can be bent to nearly zero radius (sharp bend), while brittle or work-hardened materials need large radii. It also depends on the bend ORIENTATION relative to the sheet's rolling direction (bending across the rolling direction allows smaller radii than along it, due to anisotropy). Knowing the minimum radius is essential in bent-part design: specifying a smaller radius than possible leads to crack scrap. It is common to express the minimum radius as multiples of thickness (e.g. '2t'). Enter the thickness and the material's reduction of area.
Work (Physics) Calculator
Compute work W = F·d·cos(θ). Force in N, displacement in m, angle in degrees.
Back Work Ratio (BWR)
Calculate the back work ratio (BWR) of a power cycle, BWR = w_compressor ÷ w_turbine, dividing the work consumed by the compressor (or pump) by the gross work produced by the turbine. The dimensionless result shows what fraction of turbine work is reinvested to compress the fluid. In gas turbines (Brayton cycle) the BWR is high (0.4–0.6), since compressing gas is costly; in steam Rankine cycles it is tiny (~0.01), since pumping liquid is cheap. A high BWR makes the cycle sensitive to component efficiencies. Enter the compressor work and the turbine work.
The results provided by this tool are for general informational and educational purposes only and do not constitute professional, financial, medical, legal, tax or accounting advice. Always confirm important decisions with a qualified professional and official sources.