A comparative study on historical technology of metalwork using scientific methods

比较了不同地区、不同流派、不同时代的剑枪铁材料的制作工艺。采用的科学方法有夹杂物化学分析、扫描电镜金相观察、弹道测量等。从最终包含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。剑和齿龈中夹杂物的组成有很大的不同，这意味着这两种武器使用了不同的材料。通过模拟历史锻造工艺控制铁材料中碳的含量，确定了传统锻造工艺的增碳和脱碳相对容易。（特别感谢剑匠，Hokke Sabaro Nobufusa和Eiki）叶道末进口到日本的西方枪械的材质与日本枪械不同。他们用的是高炉冶炼的铁料。我们在枪管的末端制造公螺钉和母螺钉螺纹的形状。用计算机图像测量了螺距、长度、螺纹轮廓、螺纹角度和螺纹亮度。我们测量了三支不同膛径的叶多时期火绳枪发射圆形子弹的速度。射击条件，特别是黑火药的用量是不同的，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.