The crystal structure acquired by powder steels produced from undoped iron powder and mixtures of iron with 1.0 or 1.5% graphite in hot forging was studied by X-ray diffraction and optical microscopy. The heating temperature of the samples to be forged was varied in the range 950–1150°C. The fundamentally different dependence of the lattice distortion on the heating temperature for forging of the outer and inner layers of the samples was found. The lattice imperfection increases with forging temperature in the outer layers of the hot-forged samples made of the undoped iron powder. The γ→α martensitic transformation occurs when the samples are heated above 1100°C and rapidly cooled down. The lattice imperfection decreases in the inner layers of the samples made of the undoped iron powder. In the case of carbon steel samples, the lattice distortion and hardness increase with heating temperature, reaching the maximum at 1100°C and thus characterizing the γ→α martensitic transformation. When temperature increases to 1150°C, the lattice imperfection reduces as carbon burns out more intensively at elevated temperatures, but the hardness and tensile strength decrease insignificantly. This is attributed to the quenching temperature of steel to form a ferritic cement mixture, whose structure is presented by sorbitol with a microhardness of 2700– 2900 MPa, troostite (3000 MPa), and bainite (4500 MPa).

中文翻译：

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粉末碳钢热锻结晶结构的形成

通过 X 射线衍射和光学显微镜研究了由未掺杂的铁粉和铁与 1.0% 或 1.5% 石墨的混合物在热锻中生产的粉末钢获得的晶体结构。待锻造样品的加热温度在 950-1150°C 范围内变化。发现了晶格畸变对锻造样品外层和内层的加热温度的根本不同的依赖性。在由未掺杂铁粉制成的热锻样品的外层中，晶格缺陷随着锻造温度而增加。当样品加热到 1100°C 以上并迅速冷却时，会发生 γ→α 马氏体相变。在由未掺杂的铁粉制成的样品的内层中，晶格缺陷减少。在碳钢样品的情况下，晶格畸变和硬度随着加热温度的增加而增加，在 1100°C 时达到最大值，从而表征 γ→α 马氏体转变。当温度升高到 1150°C 时，随着碳在升高的温度下更强烈地燃烧，晶格缺陷减少，但硬度和抗拉强度降低不明显。这归因于钢在淬火温度下形成铁素体水泥混合物，其结构表现为显微硬度为 2700-2900 MPa 的山梨糖醇、屈氏体（3000 MPa）和贝氏体（4500 MPa）。但硬度和抗拉强度下降不明显。这是由于钢在淬火温度下形成铁素体水泥混合物，其结构表现为显微硬度为 2700-2900 MPa 的山梨糖醇、屈氏体（3000 MPa）和贝氏体（4500 MPa）。但硬度和抗拉强度下降不明显。这是由于钢在淬火温度下形成铁素体水泥混合物，其组织表现为显微硬度为 2700-2900 MPa 的山梨糖醇、屈氏体（3000 MPa）和贝氏体（4500 MPa）。