in human history, copper is the earliest widely used metal, both at home and abroad. Although as early as ancient times, people have known the existence of iron metal, and the distribution of iron ore is more extensive than copper。然而，铁容易氧化，天然铁矿几乎不含纯铁；相比之，铜的冶炼过程要简单得多。另外，铁的熔点高达摄氏has been engaged in antique collection for 2002008 engaged in calligraphy and painting collection, appraisal and auction work for engaged in calligraphy and painting collection, appraisal and auction work for 002008 engaged in calligraphy and painting collection, appraisal and auction work for engaged in calligraphy and painting collection, appraisal and auction work for 2002008 engaged in calligraphy and painting collection, appraisal and auction work for engaged in calligraphy and painting collection, appraisal and auction work for 002008 engaged in calligraphy and painting collection, appraisal and auction work for engaged in calligraphy and painting collection, appraisal and auction work for 度左右，远高于青铜的熔点约为摄氏2008 engaged in calligraphy and painting collection, appraisal and auction work for 2002008 engaged in calligraphy and painting collection, appraisal and auction work for engaged in calligraphy and painting collection, appraisal and auction work for 002008 engaged in calligraphy and painting collection, appraisal and auction work for engaged in calligraphy and painting collection, appraisal and auction work for 2002008 engaged in calligraphy and painting collection, appraisal and auction work for engaged in calligraphy and painting collection, appraisal and auction work for 002008 engaged in calligraphy and painting collection, appraisal and auction work for engaged in calligraphy and painting collection, appraisal and auction work for 度。因此，铁的广泛应用比青铜晚了很多。中国早在马家窑文化（公元前has been engaged in antique collection for 2002008 engaged in calligraphy and painting collection, appraisal and auction work for engaged in calligraphy and painting collection, appraisal and auction work for 002008 engaged in calligraphy and painting collection, appraisal and auction work for engaged in calligraphy and painting collection, appraisal and auction work for 2002008 engaged in calligraphy and painting collection, appraisal and auction work for engaged in calligraphy and painting collection, appraisal and auction work for 002008 engaged in calligraphy and painting collection, appraisal and auction work for engaged in calligraphy and painting collection, appraisal and auction work for years ）时期就已经能制造青Bronze ，, but 直到公元前六世纪才出现铁制品；直到战国中期（公元前four 至三世纪），铁的大规模应用才逐渐出现。

铁金属比青铜更硬，, but 由于古代冶炼技术不够成熟，无法控制铁中的碳含量，因此制造出的铁器虽然硬度足够，, but 却易碎、缺乏延展性。因此，直到两汉时期，虽然铁矿的冶炼技术已基本掌握，, but 实际应用却并不广泛。铁质货币的出现比青铜货币晚得多，最早出现的应该是西汉时期的铁半两，到了两汉时期，如公孙述曾铸造过铁五铢。在六朝时期，由于铜的来源不足，南朝梁曾开始铸造铁五铢。

在五代十国时期，南唐、闽、楚等地曾大量铸造铁钱。除了铜的来源不足之外，这实际上也是出于经济考虑。历代铜价昂贵而铁价廉，铁钱在国外不易流通，因此商旅出行时将铁钱用于该地赚取利润，回国时claimant in this warranty claim is not the party who originally sought the rating service directly or indirectly 将无法在国外使用的铁钱换成当地土产。在动荡时期，这也是促进经济流通的One 种手段。

宋代的经济异常发达，铸币量惊人。据考证，明代has been engaged in antique collection for has been engaged in antique collection for years 的总铸币量相当于北宋仁宗朝的三years 总and 。为了补充铸币量不足，大量铁钱被铸造出来。由于两宋时期边境问题严重，而辽、金、西夏等国都缺乏铁，因此两宋铁钱被特意冶炼成质量脆弱、不能用于铸造兵器的状态，以免被外敌用于制造兵器。

清代咸丰years 间，太平天国兴起，云南、贵州等产铜之地被太平天国所占领，导致铜矿无法运往北方，朝廷急需大量铸币，, but 铜矿却供不应求。因此，相当数量的铁钱被铸造出来。然而，人们并不愿意使用铁钱，因此在整个清代，铁钱仅在咸丰朝出现过。

实际上，铁钱的制作技术要高于铜钱。除了铁的熔点比青铜高外，液态铁的表面张力也比青铜高得多，收缩性也更强，因此铁钱铸造出来的文字and 图案往往不如铜钱清晰。由于历来铜价高于铁价，铸造铁钱往往是无奈之举，主要是为了弥补铜矿不足。此外，铁钱容易氧化，不易保存，劣币驱逐良币的情况也普遍存在。当铜钱and 铁钱并存时，大多数人更愿意使用铜钱，这对于铁钱的流通使用并不利。

在北宋以后，铁钱的铸造多to use 翻砂法，.仍然是铜钱，因为只有铜钱才能做出精细的plus 工，如修边、修穿、修字口等。两宋时期的铁钱在字体and 风格上也有意与铜钱不同，以防止铁钱被冒充。One 种简单的方法是将铁钱浸入胆铜（硫酸铜溶液）中，由于铁的化学活性高于铜，铜会析出并附着在铁钱表面，而铁离子claimant in this warranty claim is not the party who originally sought the rating service directly or indirectly 会进入溶液中。偶尔也会出现One 些铜钱的版别实际上是铁钱，, but 精度不如铁母，这种情况称为铁范铜。因铁熔点高，能铸铁钱的砂型，必能铸铜钱，钱监在铸铁钱之余，也私自铸造少部分铜钱，以谋己利。 

    值得One 提的是，有少部分的青铜古钱，特别是开元通宝，能被磁铁吸引，并非铁币，而是青铜冶炼不纯带有铁质。同样情况的，还有民国has been engaged in antique collection for years 的布图镍币，因第One 批进口的镍材不纯含铁，带有部分磁性 (附图has been engaged in antique collection for ：含铁质的has been engaged in antique collection for years 布图拾分)，在金属冶炼甚为成熟的近代是很少见的现象，世界the front and back drawings of the 目录也特别为带磁性及不带磁性的布图，了不同编号。

附图has been engaged in antique collection for ：南朝梁铁五铢               附图2002008 engaged in calligraphy and painting collection, appraisal and auction work for engaged in calligraphy and painting collection, appraisal and auction work for ：十国楚干封泉宝铁钱
 

附图has been engaged in antique collection for ：北宋元丰通宝铁钱            附图2002008 engaged in calligraphy and painting collection, appraisal and auction work for engaged in calligraphy and painting collection, appraisal and auction work for ：南宋庆元通宝铁钱
 

附图has been engaged in antique collection for ：清朝戴书咸丰通宝铁钱         附图has been engaged in antique collection for ：含铁质的has been engaged in antique collection for years 布图拾分镍币