A comparative study on historical technology of metalwork using scientific methods

我们比较了不同地区、不同学校、不同年代制造的剑枪铁质材料的制造技术。我们使用的科学方法是夹杂物的化学分析和扫描电子显微镜的金相观察，以及弹道测量，结果方面如下：1.从端面夹杂物的方向可以区分出旧文献中记载的两种制造方法，即Udon-Bari和Maid-bar。2.剑和牙胶中夹杂物的成分有很大不同，这意味着这两种材料用于这两种武器。3.我们再现了历史上控制铁质材料奥罗什中碳含量的锻造方法，并确定用这种传统技术进行渗碳和脱碳都相对容易。(特别感谢剑史密斯、野福三郎和惠贵)4.丽岛末期输入日本的西方枪支的材料与日本的不同。他们使用高炉冶炼的铁材料。5.我们在枪管末端塑造了外螺纹和内螺纹的螺纹形状。用计算机图像测量了弹头的节距、长度、线形、线角和线宽。6.测量了三种不同口径的火箭枪在不同口径下发射的子弹速度。在不同的发射条件下，特别是黑火药量的不同，发现枪管长度对发射子弹的动能有影响。

We compared the manufacturing technique of iron materials of swords and guns made in different areas, schools and ages. The Scientific methods we used were chemical analysis of inclusion and metallographical observation using a scanning electron microscope, and ballistic measurement The results areas follows;1.From the direction of ended inclusion we can distinguish two manufacturing-methods written in old documents, i.e. Udon-bari and Maid-bar.2.The composition of inclusions in swords and gums are much different It means that the different materials were used for these two lands of weapons.3.We reenacted the historical forging way to control the carbon contents in iron materials, oroshi, and determined that both the carburization and decarburization is relatively easy by this traditional technique. (Special thanks to sword smith, Hokke Sabaro Nobufusa and Eiki)4.The material of western guns imported to Japan at the end of Yedo Period are different from Japanese ones. They used material iron smelted with blast furnace.5.We mold the shape of the threads of male and female screws at the end of gun barrels. The pitch, length, thread profile, thread angle and thread bight were measured with computer images.6.We measured the speed of round bullet fired from three matchlock guns, which were made m Yedo Period, with different bore size. The condition of firing, especially the quantities of black powder was varied It was found that barrel length would influence to the kinetic energy of fired bullet.